Playback Device Self-Calibration Using PCA-Based Room Response Estimation

ABSTRACT

Example techniques described herein relate to calibration of a playback device. Using example techniques, a playback device may self-calibrate by measuring a self-response and using a transfer function to map the self-response to an estimate of a room response. The playback device may determine calibration settings to at least partially offset acoustic characteristics of an environment surrounding the playback device as represented in the estimated room response. The transfer function may be derived from a principal component analysis of a dataset including multiple room responses, perhaps as measured during a multi-point calibration process of the playback device in various environments and conditions.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority to U.S. Pat. Application No. 63/363,433, filed Apr. 22, 2022, which is incorporated herein by reference in its entirety.

FIELD OF THE DISCLOSURE

The present disclosure is related to consumer goods and, more particularly, to methods, systems, products, features, services, and other elements directed to media playback or some aspect thereof.

BACKGROUND

Options for accessing and listening to digital audio in an out-loud setting were limited until in 2002, when SONOS, Inc. began development of a new type of playback system. Sonos then filed one of its first patent applications in 2003, entitled “Method for Synchronizing Audio Playback between Multiple Networked Devices,” and began offering its first media playback systems for sale in 2005. The Sonos Wireless Home Sound System enables people to experience music from many sources via one or more networked playback devices. Through a software control application installed on a controller (e.g., smartphone, tablet, computer, voice input device), one can play what she wants in any room having a networked playback device. Media content (e.g., songs, podcasts, video sound) can be streamed to playback devices such that each room with a playback device can play back corresponding different media content. In addition, rooms can be grouped together for synchronous playback of the same media content, and/or the same media content can be heard in all rooms synchronously.

BRIEF DESCRIPTION OF THE DRAWINGS

Features, aspects, and advantages of the presently disclosed technology may be better understood with regard to the following description, appended claims, and accompanying drawings, as listed below. A person skilled in the relevant art will understand that the features shown in the drawings are for purposes of illustrations, and variations, including different and/or additional features and arrangements thereof, are possible.

FIG. 1A is a partial cutaway view of an environment having a media playback system configured in accordance with aspects of the disclosed technology.

FIG. 1B is a schematic diagram of the media playback system of FIG. 1A and one or more networks.

FIG. 1C is a block diagram of a playback device.

FIG. 1D is a block diagram of a playback device.

FIG. 1E is a block diagram of a network microphone device.

FIG. 1F is a block diagram of a network microphone device.

FIG. 1G is a block diagram of a playback device.

FIG. 1H is a partially schematic diagram of a control device.

FIG. 2A is a diagram of a playback environment within which a playback device may be calibrated.

FIG. 2B is a representation of a database for storing room response data and corresponding playback device calibration settings.

FIG. 2C is a diagram of a playback environment within which a playback device may be calibrated.

FIG. 2D is a diagram of playback environments within which a playback device may be calibrated.

FIG. 2E is a graphical representation of a database for storing room response data and corresponding playback device calibration settings.

FIG. 3 is a flowchart of a method to calibrate a portable playback device.

FIG. 4 is a flowchart of a method to calibrate a playback device.

FIG. 5A is a first isometric view of a first example portable playback device.

FIG. 5B is a second isometric view of the first example portable playback device.

FIG. 6 is a top view of a playback device base to be used in conjunction with a portable playback device, such as the example portable playback device.

The drawings are for the purpose of illustrating example embodiments, but those of ordinary skill in the art will understand that the technology disclosed herein is not limited to the arrangements and/or instrumentality shown in the drawings.

DETAILED DESCRIPTION I. Overview

Example techniques described herein relate to calibration of a playback device. Any environment has certain acoustic characteristics (“acoustics”) that define how sound travels within that environment. For instance, with a room, the size and shape of the room, as well as objects inside that room, may define the acoustics for that room. For example, angles of walls with respect to a ceiling affect how sound reflects off the wall and the ceiling. As another example, furniture positioning in the room affects how the sound travels in the room. Various types of surfaces within the room may also affect the acoustics of that room; hard surfaces in the room may reflect sound, whereas soft surfaces may absorb sound.

Example calibration processes for a playback device may involve the playback device outputting audio content while in a given environment (e.g., a room). Then, one or more microphones detect the outputted audio content to facilitate determining an acoustic response of the room (also referred to herein as a “room response”). Calibration settings for the playback device may be determined to at least partially offset the acoustic characteristics of the environment, so as to reduce or eliminate the effect of the environment on output of the playback device.

In some examples, the microphones used to detect output of the playback device are located in a mobile device and the microphones detect output of the playback device at one or more different spatial positions in the room. In particular, a mobile device with a microphone, such as a smartphone or tablet (referred to herein as a network device) may be moved to the various locations in the room to detect the audio content. These locations may correspond to those locations where one or more listeners may experience audio playback during regular use (i.e., listening to) of the playback device. In this regard, the calibration process involves a user physically moving the network device to various locations in the room to detect the audio content at one or more spatial positions in the room. Given that this calibration involves moving the microphone to multiple locations throughout the room, this calibration may also be referred to as a “multi-location calibration” and it may generate a “multi-location acoustic response” representing room acoustics. U.S. Pat. No. 9,706,323 entitled, “Playback Device Calibration,” U.S. Pat. No. 9,763,018 entitled, “Calibration of Audio Playback Devices,”, and U.S. Pat. No. 10,299,061, entitled, “Playback Device Calibration,” which are hereby incorporated by reference in their entirety, provide examples of multi-location calibration of playback devices to account for the acoustics of a room.

Physical changes to the environment or the playback device may prompt re-calibration, as such changes may cause the output from the playback device to interact with the environment differently. For instance, changing the location (e.g., by picking up the playback device and setting it somewhere else) or positioning (e.g., by rotating the playback device to face a different direction) of the playback device may result in output from the playback device to sound differently, as the response of environment acoustics to audio output of a playback device changes based on new positioning or orientation of the playback device. Similarly, changes to the environment generally will result in different acoustic characteristics, thereby changing the interaction of the playback device with the environment.

In some circumstances, performing a multi-location calibration process with a network device such as the one described above is not feasible or practical. For example, the portable playback device might not have access to a network device that is capable of or configured for performing such a calibration process. In some examples, the portable playback device may not have access to a network device at all. Yet further, a user might not be interested in performing such a calibration especially when the process requires the user’s participation to move the microphone(s).

As such, further examples may involve a calibration of a playback device using a microphone or microphones carried on the playback device. Within examples, a playback device may determine a self-response representing output of the playback device as captured by one or more microphones carried by the playback device. This self-response may used to estimate a room response by mapping the self-response to an estimated room response using a database and/or model derived from a dataset of previously captured room responses. This room response can then be used to select or determine calibration settings that offset acoustic characteristics of the environment. Example techniques involving self-calibration of a playback device are described in U.S. Pat. No. 10,299,061 and U.S. Pat. No. 10,734,965, which are incorporated by reference herein in their entirety and attached hereto as Appendix A and Appendix B, respectively.

Example calibration techniques may utilize the echo path (i.e., the acoustic impulse response between the speaker(s) of the playback device and its microphone(s)) to predict the room response (e.g., a room average power-spectral density (PSD)). Some playback devices may include an acoustic echo canceller (e.g., to facilitate voice processing) in the presence of audio playback. Some implementations may involve measurement of the echo path from the output of the acoustic echo canceller, which may reduce the presence of echoes, reverberation, and the like from the acoustic impulse response.

After the echo path is measured, the echo path may be mapped to an estimated room response with a transfer function that has been derived from a dataset of previously captured room responses. In some cases, a least-squares regression may be used on a set of measured transfer function and measured room responses to determine a filter that minimizes the difference between the estimated room responses and the measured counterparts in the frequency domain. Other techniques for determining the transfer function may be used as well.

For instance, in some cases, principal component analysis may be used on training data to derive a filter. In particular, principal components may be extracted from training data and used to determine a mapping that projects the echo path self-response onto the room responses, which allows estimation of the room response given the echo path in a lower dimension space. Experimental data has shown improved performance with PCA-based estimation relative to direct linear mapping. Further details are found in Appendix C of the specification.

As noted above, example playback devices may utilize a model based on previously-generated room responses. Such room responses may be captured using techniques designed to measure a room average response, such as the multi-location calibrations of playback devices described above. Within examples, the training data may be generated by performing the multi-location calibration process repeatedly in various locations in a plurality of different rooms or other listening environments (e.g., outdoors). To obtain a statistically sufficient collection of different room responses and corresponding calibration settings, this process can be performed by a large number of users in a larger number of different rooms. In some examples, an initial database may be built by designated individual (e.g., product testers) and refined over time by other users.

Since different playback devices have different output characteristics, these unique characteristics must be accounted for during the process of building the database. In some cases, the playback devices used in building the database are the playback devices themselves. Alternatively, a model can be developed to translate the output of certain playback devices to represent the output of the other playback devices.

As noted above, a playback device may include its own microphone(s). During the process of building a set of training data, the playback device uses its microphone(s) to record the audio output of the playback device concurrently with the recording by the microphones of the network device. This acoustic response determined by the playback device may be referred to as a “localized acoustic response” as the acoustic response is determined based on captured audio localized at the playback device, rather than at multiple locations throughout the room via the microphone of the network device. Other terms for such as response may include a “self-response” or an “echo path,” among other examples. Such concurrent recording allows correlations to be made in the training set between the localized acoustic responses detected by the microphone(s) in the playback device and the calibration settings based on the multi-location acoustic responses detected by the microphone(s) in the network device.

In practice, local storage of the entire collection of different room responses and corresponding calibration settings may not be feasible on certain playback devices, such as portable playback devices, owing to cost and/or size considerations. As such, in example implementations, the portable playback device may include a generalization or representation of this larger remote training set. Alternatively, a playback device may include a subset of the larger remote training set. In yet further examples, a playback device may include a transfer function (e.g., a PCA-based transfer function) derived from the training set.

In operation, after a mapping is built and stored locally on the playback device, the playback device again use their own microphones to perform a self-calibration. As noted above, in such a calibration, the playback device determines a localized acoustic response for the room by outputting audio content in the room and using a microphone of the playback device to detect reflections of the audio content within the room.

The playback device then uses the localized acoustic response to estimate a room response (e.g., using a transfer function). Using the estimated room response, the playback device may determine calibration settings (e.g., a filter) that offsets acoustic characteristics of the environment as represented in the room response.

In some examples, the playback device may leverage a database of stored calibration settings for calibration. For instance, the playback device may query a database (e.g., a locally or cloud stored database) to identify a stored localized acoustic response that is substantially similar to, or that is most similar to, the localized acoustic response determined by the playback device. In particular, the playback device may use the correlated localized responses to calculate or identify stored calibration settings corresponding to the instant determined localized acoustic response. The playback device then applies to itself the identified calibration settings that are associated in the database with the instant localized acoustic response.

In some implementations, for example, a playback device stores a transfer function derived from training data including a plurality of sets of stored audio calibration area response of responses. The playback device then determines that the playback device is to perform an equalization calibration of the playback device. In response to the determination that the playback device is to perform the equalization calibration, the playback device initiates the equalization calibration. The equalization calibration comprises (i) outputting, via the speaker, audio content (ii) capturing, via the microphone, audio data representing reflections of the audio content within an area in which the playback device is located (iii) based on at least the captured audio data, determining an acoustic response of the area in which the playback device is located, and (iv) applying to the audio content, a set of audio calibration settings corresponding to the determined acoustic area response.

While some examples described herein may refer to functions performed by given actors such as “users,” “listeners,” and/or other entities, it should be understood that this is for purposes of explanation only. The claims should not be interpreted to require action by any such example actor unless explicitly required by the language of the claims themselves.

In the Figures, identical reference numbers identify generally similar, and/or identical, elements. To facilitate the discussion of any particular element, the most significant digit or digits of a reference number refers to the Figure in which that element is first introduced. For example, element 110 a is first introduced and discussed with reference to FIG. 1A. Many of the details, dimensions, angles and other features shown in the Figures are merely illustrative of particular embodiments of the disclosed technology. Accordingly, other embodiments can have other details, dimensions, angles and features without departing from the spirit or scope of the disclosure. In addition, those of ordinary skill in the art will appreciate that further embodiments of the various disclosed technologies can be practiced without several of the details described below.

II. Suitable Operating Environment

FIG. 1A is a partial cutaway view of a media playback system 100 distributed in an environment 101 (e.g., a house). The media playback system 100 comprises one or more playback devices 110 (identified individually as playback devices 110 a-n), one or more network microphone devices (“NMDs”) 120 (identified individually as NMDs 120 a-c), and one or more control devices 130 (identified individually as control devices 130 a and 130 b).

As used herein the term “playback device” can generally refer to a network device configured to receive, process, and output data of a media playback system. For example, a playback device can be a network device that receives and processes audio content. In some embodiments, a playback device includes one or more transducers or speakers powered by one or more amplifiers. In other embodiments, however, a playback device includes one of (or neither of) the speaker and the amplifier. For instance, a playback device can comprise one or more amplifiers configured to drive one or more speakers external to the playback device via a corresponding wire or cable.

Moreover, as used herein the term NMD (i.e., a “network microphone device”) can generally refer to a network device that is configured for audio detection. In some embodiments, an NMD is a stand-alone device configured primarily for audio detection. In other embodiments, an NMD is incorporated into a playback device (or vice versa).

The term “control device” can generally refer to a network device configured to perform functions relevant to facilitating user access, control, and/or configuration of the media playback system 100.

Each of the playback devices 110 is configured to receive audio signals or data from one or more media sources (e.g., one or more remote servers, one or more local devices) and play back the received audio signals or data as sound. The one or more NMDs 120 are configured to receive spoken word commands, and the one or more control devices 130 are configured to receive user input. In response to the received spoken word commands and/or user input, the media playback system 100 can play back audio via one or more of the playback devices 110. In certain embodiments, the playback devices 110 are configured to commence playback of media content in response to a trigger. For instance, one or more of the playback devices 110 can be configured to play back a morning playlist upon detection of an associated trigger condition (e.g., presence of a user in a kitchen, detection of a coffee machine operation). In some embodiments, for example, the media playback system 100 is configured to play back audio from a first playback device (e.g., the playback device 100 a) in synchrony with a second playback device (e.g., the playback device 100 b). Interactions between the playback devices 110, NMDs 120, and/or control devices 130 of the media playback system 100 configured in accordance with the various embodiments of the disclosure are described in greater detail below with respect to FIGS. 1B-1H.

In the illustrated embodiment of FIG. 1A, the environment 101 comprises a household having several rooms, spaces, and/or playback zones, including (clockwise from upper left) a master bathroom 101 a, a master bedroom 101 b, a second bedroom 101 c, a family room or den 101 d, an office 101 e, a living room 101 f, a dining room 101 g, a kitchen 101 h, and an outdoor patio 101 i. While certain embodiments and examples are described below in the context of a home environment, the technologies described herein may be implemented in other types of environments. In some embodiments, for example, the media playback system 100 can be implemented in one or more commercial settings (e.g., a restaurant, mall, airport, hotel, a retail or other store), one or more vehicles (e.g., a sports utility vehicle, bus, car, a ship, a boat, an airplane), multiple environments (e.g., a combination of home and vehicle environments), and/or another suitable environment where multi-zone audio may be desirable.

The media playback system 100 can comprise one or more playback zones, some of which may correspond to the rooms in the environment 101. The media playback system 100 can be established with one or more playback zones, after which additional zones may be added, or removed to form, for example, the configuration shown in FIG. 1A. Each zone may be given a name according to a different room or space such as the office 101 e, master bathroom 101 a, master bedroom 101 b, the second bedroom 101 c, kitchen 101 h, dining room 101 g, living room 101 f, and/or the balcony 101 i. In some aspects, a single playback zone may include multiple rooms or spaces. In certain aspects, a single room or space may include multiple playback zones.

In the illustrated embodiment of FIG. 1A, the master bathroom 101 a, the second bedroom 101 c, the office 101 e, the living room 101 f, the dining room 101 g, the kitchen 101 h, and the outdoor patio 101 i each include one playback device 110, and the master bedroom 101 b and the den 101 d include a plurality of playback devices 110. In the master bedroom 101 b, the playback devices 110 l and 110 m may be configured, for example, to play back audio content in synchrony as individual ones of playback devices 110, as a bonded playback zone, as a consolidated playback device, and/or any combination thereof. Similarly, in the den 101 d, the playback devices 110 h-j can be configured, for instance, to play back audio content in synchrony as individual ones of playback devices 110, as one or more bonded playback devices, and/or as one or more consolidated playback devices. Additional details regarding bonded and consolidated playback devices are described below with respect to FIGS. 1B and 1E.

In some aspects, one or more of the playback zones in the environment 101 may each be playing different audio content. For instance, a user may be grilling on the patio 101 i and listening to hip hop music being played by the playback device 110 c while another user is preparing food in the kitchen 101 h and listening to classical music played by the playback device 110 b. In another example, a playback zone may play the same audio content in synchrony with another playback zone. For instance, the user may be in the office 101 e listening to the playback device 110 f playing back the same hip hop music being played back by playback device 110 c on the patio 101 i. In some aspects, the playback devices 110 c and 110 f play back the hip hop music in synchrony such that the user perceives that the audio content is being played seamlessly (or at least substantially seamlessly) while moving between different playback zones. Additional details regarding audio playback synchronization among playback devices and/or zones can be found, for example, in U.S. Pat. No. 8,234,395 entitled, “System and method for synchronizing operations among a plurality of independently clocked digital data processing devices,” which is incorporated herein by reference in its entirety.

A. Suitable Media Playback System

FIG. 1B is a schematic diagram of the media playback system 100 and a cloud network 102. For ease of illustration, certain devices of the media playback system 100 and the cloud network 102 are omitted from FIG. 1B. One or more communication links 103 (referred to hereinafter as “the links 103”) communicatively couple the media playback system 100 and the cloud network 102.

The links 103 can comprise, for example, one or more wired networks, one or more wireless networks, one or more wide area networks (WAN), one or more local area networks (LAN), one or more personal area networks (PAN), one or more telecommunication networks (e.g., one or more Global System for Mobiles (GSM) networks, Code Division Multiple Access (CDMA) networks, Long-Term Evolution (LTE) networks, 5G communication network networks, and/or other suitable data transmission protocol networks), etc. The cloud network 102 is configured to deliver media content (e.g., audio content, video content, photographs, social media content) to the media playback system 100 in response to a request transmitted from the media playback system 100 via the links 103. In some embodiments, the cloud network 102 is further configured to receive data (e.g. voice input data) from the media playback system 100 and correspondingly transmit commands and/or media content to the media playback system 100.

The cloud network 102 comprises computing devices 106 (identified separately as a first computing device 106 a, a second computing device 106 b, and a third computing device 106 c). The computing devices 106 can comprise individual computers or servers, such as, for example, a media streaming service server storing audio and/or other media content, a voice service server, a social media server, a media playback system control server, etc. In some embodiments, one or more of the computing devices 106 comprise modules of a single computer or server. In certain embodiments, one or more of the computing devices 106 comprise one or more modules, computers, and/or servers. Moreover, while the cloud network 102 is described above in the context of a single cloud network, in some embodiments the cloud network 102 comprises a plurality of cloud networks comprising communicatively coupled computing devices. Furthermore, while the cloud network 102 is shown in FIG. 1B as having three of the computing devices 106, in some embodiments, the cloud network 102 comprises fewer (or more than) three computing devices 106.

The media playback system 100 is configured to receive media content from the networks 102 via the links 103. The received media content can comprise, for example, a Uniform Resource Identifier (URI) and/or a Uniform Resource Locator (URL). For instance, in some examples, the media playback system 100 can stream, download, or otherwise obtain data from a URI or a URL corresponding to the received media content. A network 104 communicatively couples the links 103 and at least a portion of the devices (e.g., one or more of the playback devices 110, NMDs 120, and/or control devices 130) of the media playback system 100. The network 104 can include, for example, a wireless network (e.g., a WiFi network, a Bluetooth, a Z-Wave network, a ZigBee, and/or other suitable wireless communication protocol network) and/or a wired network (e.g., a network comprising Ethernet, Universal Serial Bus (USB), and/or another suitable wired communication). As those of ordinary skill in the art will appreciate, as used herein, “WiFi” can refer to several different communication protocols including, for example, Institute of Electrical and Electronics Engineers (IEEE) 802.11a, 802.11b, 802.11 g, 802.11n, 802.11ac, 802.11ac, 802.11ad, 802.11af, 802.11ah, 802.11ai, 802.11aj, 802.11aq, 802.11ax, 802.11ay, 802.15, etc. transmitted at 2.4 Gigahertz (GHz), 5 GHz, and/or another suitable frequency.

In some embodiments, the network 104 comprises a dedicated communication network that the media playback system 100 uses to transmit messages between individual devices and/or to transmit media content to and from media content sources (e.g., one or more of the computing devices 106). In certain embodiments, the network 104 is configured to be accessible only to devices in the media playback system 100, thereby reducing interference and competition with other household devices. In other embodiments, however, the network 104 comprises an existing household communication network (e.g., a household WiFi network). In some embodiments, the links 103 and the network 104 comprise one or more of the same networks. In some aspects, for example, the links 103 and the network 104 comprise a telecommunication network (e.g., an LTE network, a 5G network). Moreover, in some embodiments, the media playback system 100 is implemented without the network 104, and devices comprising the media playback system 100 can communicate with each other, for example, via one or more direct connections, PANs, telecommunication networks, and/or other suitable communication links.

In some embodiments, audio content sources may be regularly added or removed from the media playback system 100. In some embodiments, for example, the media playback system 100 performs an indexing of media items when one or more media content sources are updated, added to, and/or removed from the media playback system 100. The media playback system 100 can scan identifiable media items in some or all folders and/or directories accessible to the playback devices 110, and generate or update a media content database comprising metadata (e.g., title, artist, album, track length) and other associated information (e.g., URIs, URLs) for each identifiable media item found. In some embodiments, for example, the media content database is stored on one or more of the playback devices 110, network microphone devices 120, and/or control devices 130.

In the illustrated embodiment of FIG. 1B, the playback devices 110 l and 110 m comprise a group 107 a. The playback devices 110 l and 110 m can be positioned in different rooms in a household and be grouped together in the group 107 a on a temporary or permanent basis based on user input received at the control device 130 a and/or another control device 130 in the media playback system 100. When arranged in the group 107 a, the playback devices 110 l and 110 m can be configured to play back the same or similar audio content in synchrony from one or more audio content sources. In certain embodiments, for example, the group 107 a comprises a bonded zone in which the playback devices 110 l and 110 m comprise left audio and right audio channels, respectively, of multi-channel audio content, thereby producing or enhancing a stereo effect of the audio content. In some embodiments, the group 107 a includes additional playback devices 110. In other embodiments, however, the media playback system 100 omits the group 107 a and/or other grouped arrangements of the playback devices 110.

The media playback system 100 includes the NMDs 120 a and 120 d, each comprising one or more microphones configured to receive voice utterances from a user. In the illustrated embodiment of FIG. 1B, the NMD 120 a is a standalone device and the NMD 120 d is integrated into the playback device 110 n. The NMD 120 a, for example, is configured to receive voice input 121 from a user 123. In some embodiments, the NMD 120 a transmits data associated with the received voice input 121 to a voice assistant service (VAS) configured to (i) process the received voice input data and (ii) transmit a corresponding command to the media playback system 100. In some aspects, for example, the computing device 106 c comprises one or more modules and/or servers of a VAS (e.g., a VAS operated by one or more of SONOS®, AMAZON®, GOOGLE® APPLE®, MICROSOFT®). The computing device 106 c can receive the voice input data from the NMD 120 a via the network 104 and the links 103. In response to receiving the voice input data, the computing device 106 c processes the voice input data (i.e., “Play Hey Jude by The Beatles”), and determines that the processed voice input includes a command to play a song (e.g., “Hey Jude”). The computing device 106 c accordingly transmits commands to the media playback system 100 to play back “Hey Jude” by the Beatles from a suitable media service (e.g., via one or more of the computing devices 106) on one or more of the playback devices 110.

B. Suitable Playback Devices

FIG. 1C is a block diagram of the playback device 110 a comprising an input/output 111. The input/output 111 can include an analog I/O 111 a (e.g., one or more wires, cables, and/or other suitable communication links configured to carry analog signals) and/or a digital I/O 111 b (e.g., one or more wires, cables, or other suitable communication links configured to carry digital signals). In some embodiments, the analog I/O 111 a is an audio line-in input connection comprising, for example, an auto-detecting 3.5 mm audio line-in connection. In some embodiments, the digital I/O 111 b comprises a Sony/Philips Digital Interface Format (S/PDIF) communication interface and/or cable and/or a Toshiba Link (TOSLINK) cable. In some embodiments, the digital I/O 111 b comprises an High-Definition Multimedia Interface (HDMI) interface and/or cable. In some embodiments, the digital I/O 111 b includes one or more wireless communication links comprising, for example, a radio frequency (RF), infrared, WiFi, Bluetooth, or another suitable communication protocol. In certain embodiments, the analog I/O 111 a and the digital 111 b comprise interfaces (e.g., ports, plugs, jacks) configured to receive connectors of cables transmitting analog and digital signals, respectively, without necessarily including cables.

The playback device 110 a, for example, can receive media content (e.g., audio content comprising music and/or other sounds) from a local audio source 105 via the input/output 111 (e.g., a cable, a wire, a PAN, a Bluetooth connection, an ad hoc wired or wireless communication network, and/or another suitable communication link). The local audio source 105 can comprise, for example, a mobile device (e.g., a smartphone, a tablet, a laptop computer) or another suitable audio component (e.g., a television, a desktop computer, an amplifier, a phonograph, a Blu-ray player, a memory storing digital media files). In some aspects, the local audio source 105 includes local music libraries on a smartphone, a computer, a networked-attached storage (NAS), and/or another suitable device configured to store media files. In certain embodiments, one or more of the playback devices 110, NMDs 120, and/or control devices 130 comprise the local audio source 105. In other embodiments, however, the media playback system omits the local audio source 105 altogether. In some embodiments, the playback device 110 a does not include an input/output 111 and receives all audio content via the network 104.

The playback device 110 a further comprises electronics 112, a user interface 113 (e.g., one or more buttons, knobs, dials, touch-sensitive surfaces, displays, touchscreens), and one or more transducers 114 (referred to hereinafter as “the transducers 114”). The electronics 112 is configured to receive audio from an audio source (e.g., the local audio source 105) via the input/output 111, one or more of the computing devices 106 a-c via the network 104 (FIG. 1B)), amplify the received audio, and output the amplified audio for playback via one or more of the transducers 114. In some embodiments, the playback device 110 a optionally includes one or more microphones 115 (e.g., a single microphone, a plurality of microphones, a microphone array) (hereinafter referred to as “the microphones 115”). In certain embodiments, for example, the playback device 110 a having one or more of the optional microphones 115 can operate as an NMD configured to receive voice input from a user and correspondingly perform one or more operations based on the received voice input.

In the illustrated embodiment of FIG. 1C, the electronics 112 comprise one or more processors 112 a (referred to hereinafter as “the processors 112 a”), memory 112 b, software components 112 c, a network interface 112 d, one or more audio processing components 112 g (referred to hereinafter as “the audio components 112 g”), one or more audio amplifiers 112 h (referred to hereinafter as “the amplifiers 112 h”), and power 112 i (e.g., one or more power supplies, power cables, power receptacles, batteries, induction coils, Power-over Ethernet (POE) interfaces, and/or other suitable sources of electric power). In some embodiments, the electronics 112 optionally include one or more other components 112 j (e.g., one or more sensors, video displays, touchscreens, battery charging bases).

The processors 112 a can comprise clock-driven computing component(s) configured to process data, and the memory 112 b can comprise a computer-readable medium (e.g., a tangible, non-transitory computer-readable medium, data storage loaded with one or more of the software components 112 c) configured to store instructions for performing various operations and/or functions. The processors 112 a are configured to execute the instructions stored on the memory 112 b to perform one or more of the operations. The operations can include, for example, causing the playback device 110 a to retrieve audio data from an audio source (e.g., one or more of the computing devices 106 a-c (FIG. 1B)), and/or another one of the playback devices 110. In some embodiments, the operations further include causing the playback device 110 a to send audio data to another one of the playback devices 110 a and/or another device (e.g., one of the NMDs 120). Certain embodiments include operations causing the playback device 110 a to pair with another of the one or more playback devices 110 to enable a multi-channel audio environment (e.g., a stereo pair, a bonded zone).

The processors 112 a can be further configured to perform operations causing the playback device 110 a to synchronize playback of audio content with another of the one or more playback devices 110. As those of ordinary skill in the art will appreciate, during synchronous playback of audio content on a plurality of playback devices, a listener will preferably be unable to perceive time-delay differences between playback of the audio content by the playback device 110 a and the other one or more other playback devices 110. Additional details regarding audio playback synchronization among playback devices can be found, for example, in U.S. Pat. No. 8,234,395, which was incorporated by reference above.

In some embodiments, the memory 112 b is further configured to store data associated with the playback device 110 a, such as one or more zones and/or zone groups of which the playback device 110 a is a member, audio sources accessible to the playback device 110 a, and/or a playback queue that the playback device 110 a (and/or another of the one or more playback devices) can be associated with. The stored data can comprise one or more state variables that are periodically updated and used to describe a state of the playback device 110 a. The memory 112 b can also include data associated with a state of one or more of the other devices (e.g., the playback devices 110, NMDs 120, control devices 130) of the media playback system 100. In some aspects, for example, the state data is shared during predetermined intervals of time (e.g., every 5 seconds, every 10 seconds, every 60 seconds) among at least a portion of the devices of the media playback system 100, so that one or more of the devices have the most recent data associated with the media playback system 100.

The network interface 112 d is configured to facilitate a transmission of data between the playback device 110 a and one or more other devices on a data network such as, for example, the links 103 and/or the network 104 (FIG. 1B). The network interface 112 d is configured to transmit and receive data corresponding to media content (e.g., audio content, video content, text, photographs) and other signals (e.g., non-transitory signals) comprising digital packet data including an Internet Protocol (IP)-based source address and/or an IP-based destination address. The network interface 112 d can parse the digital packet data such that the electronics 112 properly receives and processes the data destined for the playback device 110 a.

In the illustrated embodiment of FIG. 1C, the network interface 112 d comprises one or more wireless interfaces 112 e (referred to hereinafter as “the wireless interface 112 e”). The wireless interface 112 e (e.g., a suitable interface comprising one or more antennae) can be configured to wirelessly communicate with one or more other devices (e.g., one or more of the other playback devices 110, NMDs 120, and/or control devices 130) that are communicatively coupled to the network 104 (FIG. 1B) in accordance with a suitable wireless communication protocol (e.g., WiFi, Bluetooth, LTE). In some embodiments, the network interface 112 d optionally includes a wired interface 112 f (e.g., an interface or receptacle configured to receive a network cable such as an Ethernet, a USB-A, USB-C, and/or Thunderbolt cable) configured to communicate over a wired connection with other devices in accordance with a suitable wired communication protocol. In certain embodiments, the network interface 112 d includes the wired interface 112 f and excludes the wireless interface 112 e. In some embodiments, the electronics 112 excludes the network interface 112 d altogether and transmits and receives media content and/or other data via another communication path (e.g., the input/output 111).

The audio components 112 g are configured to process and/or filter data comprising media content received by the electronics 112 (e.g., via the input/output 111 and/or the network interface 112 d) to produce output audio signals. In some embodiments, the audio processing components 112 g comprise, for example, one or more digital-to-analog converters (DAC), audio preprocessing components, audio enhancement components, a digital signal processors (DSPs), and/or other suitable audio processing components, modules, circuits, etc. In certain embodiments, one or more of the audio processing components 112 g can comprise one or more subcomponents of the processors 112 a. In some embodiments, the electronics 112 omits the audio processing components 112 g. In some aspects, for example, the processors 112 a execute instructions stored on the memory 112 b to perform audio processing operations to produce the output audio signals.

The amplifiers 112 h are configured to receive and amplify the audio output signals produced by the audio processing components 112 g and/or the processors 112 a. The amplifiers 112 h can comprise electronic devices and/or components configured to amplify audio signals to levels sufficient for driving one or more of the transducers 114. In some embodiments, for example, the amplifiers 112 h include one or more switching or class-D power amplifiers. In other embodiments, however, the amplifiers include one or more other types of power amplifiers (e.g., linear gain power amplifiers, class-A amplifiers, class-B amplifiers, class-AB amplifiers, class-C amplifiers, class-D amplifiers, class-E amplifiers, class-F amplifiers, class-G and/or class H amplifiers, and/or another suitable type of power amplifier). In certain embodiments, the amplifiers 112 h comprise a suitable combination of two or more of the foregoing types of power amplifiers. Moreover, in some embodiments, individual ones of the amplifiers 112 h correspond to individual ones of the transducers 114. In other embodiments, however, the electronics 112 includes a single one of the amplifiers 112 h configured to output amplified audio signals to a plurality of the transducers 114. In some other embodiments, the electronics 112 omits the amplifiers 112 h.

The transducers 114 (e.g., one or more speakers and/or speaker drivers) receive the amplified audio signals from the amplifier 112 h and render or output the amplified audio signals as sound (e.g., audible sound waves having a frequency between about 20 Hertz (Hz) and 20 kilohertz (kHz)). In some embodiments, the transducers 114 can comprise a single transducer. In other embodiments, however, the transducers 114 comprise a plurality of audio transducers. In some embodiments, the transducers 114 comprise more than one type of transducer. For example, the transducers 114 can include one or more low frequency transducers (e.g., subwoofers, woofers), mid-range frequency transducers (e.g., mid-range transducers, mid-woofers), and one or more high frequency transducers (e.g., one or more tweeters). As used herein, “low frequency” can generally refer to audible frequencies below about 500 Hz, “mid-range frequency” can generally refer to audible frequencies between about 500 Hz and about 2 kHz, and “high frequency” can generally refer to audible frequencies above 2 kHz. In certain embodiments, however, one or more of the transducers 114 comprise transducers that do not adhere to the foregoing frequency ranges. For example, one of the transducers 114 may comprise a mid-woofer transducer configured to output sound at frequencies between about 200 Hz and about 5 kHz.

By way of illustration, SONOS, Inc. presently offers (or has offered) for sale certain playback devices including, for example, a “SONOS ONE,” “PLAY:1,” “PLAY:3,” “PLAY:5,” “PLAYBAR,” “PLAYBASE,” “CONNECT:AMP,” “CONNECT,” and “SUB.” Other suitable playback devices may additionally or alternatively be used to implement the playback devices of example embodiments disclosed herein. Additionally, one of ordinary skilled in the art will appreciate that a playback device is not limited to the examples described herein or to SONOS product offerings. In some embodiments, for example, one or more playback devices 110 comprises wired or wireless headphones (e.g., over-the-ear headphones, on-ear headphones, in-ear earphones). In other embodiments, one or more of the playback devices 110 comprise a docking station and/or an interface configured to interact with a docking station for personal mobile media playback devices. In certain embodiments, a playback device may be integral to another device or component such as a television, a lighting fixture, or some other device for indoor or outdoor use. In some embodiments, a playback device omits a user interface and/or one or more transducers. For example, FIG. 1D is a block diagram of a playback device 110 p comprising the input/output 111 and electronics 112 without the user interface 113 or transducers 114.

FIG. 1E is a block diagram of a bonded playback device 110 q comprising the playback device 110 a (FIG. 1C) sonically bonded with the playback device 110 i (e.g., a subwoofer) (FIG. 1A). In the illustrated embodiment, the playback devices 110 a and 110 i are separate ones of the playback devices 110 housed in separate enclosures. In some embodiments, however, the bonded playback device 110 q comprises a single enclosure housing both the playback devices 110 a and 110 i. The bonded playback device 110 q can be configured to process and reproduce sound differently than an unbonded playback device (e.g., the playback device 110 a of FIG. 1C) and/or paired or bonded playback devices (e.g., the playback devices 110 l and 110 m of FIG. 1B). In some embodiments, for example, the playback device 110 a is full-range playback device configured to render low frequency, mid-range frequency, and high frequency audio content, and the playback device 110 i is a subwoofer configured to render low frequency audio content. In some aspects, the playback device 110 a, when bonded with the first playback device, is configured to render only the mid-range and high frequency components of a particular audio content, while the playback device 110 i renders the low frequency component of the particular audio content. In some embodiments, the bonded playback device 110 q includes additional playback devices and/or another bonded playback device.

C. Suitable Network Microphone Devices (NMDs)

FIG. 1F is a block diagram of the NMD 120 a (FIGS. 1A and 1B). The NMD 120 a includes one or more voice processing components 124 (hereinafter “the voice components 124”) and several components described with respect to the playback device 110 a (FIG. 1C) including the processors 112 a, the memory 112 b, and the microphones 115. The NMD 120 a optionally comprises other components also included in the playback device 110 a (FIG. 1C), such as the user interface 113 and/or the transducers 114. In some embodiments, the NMD 120 a is configured as a media playback device (e.g., one or more of the playback devices 110), and further includes, for example, one or more of the audio components 112 g (FIG. 1C), the amplifiers 114, and/or other playback device components. In certain embodiments, the NMD 120 a comprises an Internet of Things (IoT) device such as, for example, a thermostat, alarm panel, fire and/or smoke detector, etc. In some embodiments, the NMD 120 a comprises the microphones 115, the voice processing 124, and only a portion of the components of the electronics 112 described above with respect to FIG. 1B. In some aspects, for example, the NMD 120 a includes the processor 112 a and the memory 112 b (FIG. 1B), while omitting one or more other components of the electronics 112. In some embodiments, the NMD 120 a includes additional components (e.g., one or more sensors, cameras, thermometers, barometers, hygrometers).

In some embodiments, an NMD can be integrated into a playback device. FIG. 1G is a block diagram of a playback device 110 r comprising an NMD 120 d. The playback device 110 r can comprise many or all of the components of the playback device 110 a and further include the microphones 115 and voice processing 124 (FIG. 1F). The playback device 110 r optionally includes an integrated control device 130 c. The control device 130 c can comprise, for example, a user interface (e.g., the user interface 113 of FIG. 1B) configured to receive user input (e.g., touch input, voice input) without a separate control device. In other embodiments, however, the playback device 110 r receives commands from another control device (e.g., the control device 130 a of FIG. 1B).

Referring again to FIG. 1F, the microphones 115 are configured to acquire, capture, and/or receive sound from an environment (e.g., the environment 101 of FIG. 1A) and/or a room in which the NMD 120 a is positioned. The received sound can include, for example, vocal utterances, audio played back by the NMD 120 a and/or another playback device, background voices, ambient sounds, etc. The microphones 115 convert the received sound into electrical signals to produce microphone data. The voice processing 124 receives and analyzes the microphone data to determine whether a voice input is present in the microphone data. The voice input can comprise, for example, an activation word followed by an utterance including a user request. As those of ordinary skill in the art will appreciate, an activation word is a word or other audio cue that signifying a user voice input. For instance, in querying the AMAZON® VAS, a user might speak the activation word “Alexa.” Other examples include “Ok, Google” for invoking the GOOGLE® VAS and “Hey, Siri” for invoking the APPLE® VAS.

After detecting the activation word, voice processing 124 monitors the microphone data for an accompanying user request in the voice input. The user request may include, for example, a command to control a third-party device, such as a thermostat (e.g., NEST® thermostat), an illumination device (e.g., a PHILIPS HUE ® lighting device), or a media playback device (e.g., a Sonos® playback device). For example, a user might speak the activation word “Alexa” followed by the utterance “set the thermostat to 68 degrees” to set a temperature in a home (e.g., the environment 101 of FIG. 1A). The user might speak the same activation word followed by the utterance “turn on the living room” to turn on illumination devices in a living room area of the home. The user may similarly speak an activation word followed by a request to play a particular song, an album, or a playlist of music on a playback device in the home.

D. Suitable Control Devices

FIG. 1H is a partially schematic diagram of the control device 130 a (FIGS. 1A and 1B). As used herein, the term “control device” can be used interchangeably with “controller” or “control system.” Among other features, the control device 130 a is configured to receive user input related to the media playback system 100 and, in response, cause one or more devices in the media playback system 100 to perform an action(s) or operation(s) corresponding to the user input. In the illustrated embodiment, the control device 130 a comprises a smartphone (e.g., an iPhone™, an Android phone) on which media playback system controller application software is installed. In some embodiments, the control device 130 a comprises, for example, a tablet (e.g., an iPad™), a computer (e.g., a laptop computer, a desktop computer), and/or another suitable device (e.g., a television, an automobile audio head unit, an IoT device). In certain embodiments, the control device 130 a comprises a dedicated controller for the media playback system 100. In other embodiments, as described above with respect to FIG. 1G, the control device 130 a is integrated into another device in the media playback system 100 (e.g., one more of the playback devices 110, NMDs 120, and/or other suitable devices configured to communicate over a network).

The control device 130 a includes electronics 132, a user interface 133, one or more speakers 134, and one or more microphones 135. The electronics 132 comprise one or more processors 132 a (referred to hereinafter as “the processors 132 a”), a memory 132 b, software components 132 c, and a network interface 132 d. The processor 132 a can be configured to perform functions relevant to facilitating user access, control, and configuration of the media playback system 100. The memory 132 b can comprise data storage that can be loaded with one or more of the software components executable by the processor 132 a to perform those functions. The software components 132 c can comprise applications and/or other executable software configured to facilitate control of the media playback system 100. The memory 112 b can be configured to store, for example, the software components 132 c, media playback system controller application software, and/or other data associated with the media playback system 100 and the user.

The network interface 132 d is configured to facilitate network communications between the control device 130 a and one or more other devices in the media playback system 100, and/or one or more remote devices. In some embodiments, the network interface 132 is configured to operate according to one or more suitable communication industry standards (e.g., infrared, radio, wired standards including IEEE 802.3, wireless standards including IEEE 802.11a, 802.11b, 802.11 g, 802.11n, 802.11ac, 802.15, 4G, LTE). The network interface 132 d can be configured, for example, to transmit data to and/or receive data from the playback devices 110, the NMDs 120, other ones of the control devices 130, one of the computing devices 106 of FIG. 1B, devices comprising one or more other media playback systems, etc. The transmitted and/or received data can include, for example, playback device control commands, state variables, playback zone and/or zone group configurations. For instance, based on user input received at the user interface 133, the network interface 132 d can transmit a playback device control command (e.g., volume control, audio playback control, audio content selection) from the control device 130 a to one or more of the playback devices 100. The network interface 132 d can also transmit and/or receive configuration changes such as, for example, adding/removing one or more playback devices 100 to/from a zone, adding/removing one or more zones to/from a zone group, forming a bonded or consolidated player, separating one or more playback devices from a bonded or consolidated player, among others.

The user interface 133 is configured to receive user input and can facilitate ‘control of the media playback system 100. The user interface 133 includes media content art 133 a (e.g., album art, lyrics, videos), a playback status indicator 133 b (e.g., an elapsed and/or remaining time indicator), media content information region 133 c, a playback control region 133 d, and a zone indicator 133 e. The media content information region 133 c can include a display of relevant information (e.g., title, artist, album, genre, release year) about media content currently playing and/or media content in a queue or playlist. The playback control region 133 d can include selectable (e.g., via touch input and/or via a cursor or another suitable selector) icons to cause one or more playback devices in a selected playback zone or zone group to perform playback actions such as, for example, play or pause, fast forward, rewind, skip to next, skip to previous, enter/exit shuffle mode, enter/exit repeat mode, enter/exit cross fade mode, etc. The playback control region 133 d may also include selectable icons to modify equalization settings, playback volume, and/or other suitable playback actions. In the illustrated embodiment, the user interface 133 comprises a display presented on a touch screen interface of a smartphone (e.g., an iPhone™, an Android phone). In some embodiments, however, user interfaces of varying formats, styles, and interactive sequences may alternatively be implemented on one or more network devices to provide comparable control access to a media playback system.

The one or more speakers 134 (e.g., one or more transducers) can be configured to output sound to the user of the control device 130 a. In some embodiments, the one or more speakers comprise individual transducers configured to correspondingly output low frequencies, mid-range frequencies, and/or high frequencies. In some aspects, for example, the control device 130 a is configured as a playback device (e.g., one of the playback devices 110). Similarly, in some embodiments the control device 130 a is configured as an NMD (e.g., one of the NMDs 120), receiving voice commands and other sounds via the one or more microphones 135.

The one or more microphones 135 can comprise, for example, one or more condenser microphones, electret condenser microphones, dynamic microphones, and/or other suitable types of microphones or transducers. In some embodiments, two or more of the microphones 135 are arranged to capture location information of an audio source (e.g., voice, audible sound) and/or configured to facilitate filtering of background noise. Moreover, in certain embodiments, the control device 130 a is configured to operate as playback device and an NMD. In other embodiments, however, the control device 130 a omits the one or more speakers 134 and/or the one or more microphones 135. For instance, the control device 130 a may comprise a device (e.g., a thermostat, an IoT device, a network device) comprising a portion of the electronics 132 and the user interface 133 (e.g., a touch screen) without any speakers or microphones.

III. Example Systems and Methods for Calibrating a Playback Device

As discussed above, in some examples, a playback device is configured to calibrate itself to offset (or otherwise account for) an acoustic response of a room in which the playback device is located. The playback device performs this self-calibration by leveraging a database that is populated with calibration settings and/or reference room responses that were determined for a number of other playback devices. In some embodiments, the calibration settings and/or reference room responses stored in the database are determined based on multi-location acoustic responses for the rooms of the other playback devices recorded previously on mobile devices, such as a smart phone or tablet.

FIG. 2A depicts an example environment for using a multi-location acoustic response of a room to determine calibration settings for a playback device. As shown in FIG. 2A, a playback device 210 a and a network device 230 are located in a room 201 a. The playback device 210 a may be similar to any of the playback devices 110 depicted in FIGS. 1A-1E and 1G, and the network device 230 may be similar to any of the NMDs 120 or controllers 130 depicted in FIGS. 1A-1B and 1F-1H. One or both of the playback device 210 a and the network device 230 are in communication, either directly or indirectly, with a computing device 206. The computing device 206 may be similar to any of the computing devices 106 depicted in FIG. 1B. For instance, the computing device 206 may be a server located remotely from the room 201 a and connected to the playback device 210 a and/or the network device 230 over a wired or wireless communication network.

In practice, the playback device 210 a outputs audio content via one or more transducers (e.g., one or more speakers and/or speaker drivers) of the playback device 210 a. In one example, the audio content is output using a test signal or measurement signal representative of audio content that may be played by the playback device 210 a during regular use by a user. Accordingly, the audio content may include content with frequencies substantially covering a renderable frequency range of the playback device 210 a or a frequency range audible to a human. In one case, the audio content is output using an audio signal designed specifically for use when calibrating playback devices such as the playback device 210 a being calibrated in examples discussed herein. In another case, the audio content is an audio track that is a favorite of a user of the playback device 210 a, or a commonly played audio track by the playback device 210 a. Other examples are also possible.

While the playback device 210 a outputs the audio content, the network device 230 moves to various locations within the room 201 a. For instance, the network device 230 may move between a first physical location and a second physical location within the room 201 a. As shown in FIG. 2A, the first physical location may be the point (a), and the second physical location may be the point (b). While moving from the first physical location (a) to the second physical location (b), the network device 230 may traverse locations within the room 201 a where one or more listeners may experience audio playback during regular use of the playback device 210 a. For instance, as shown, the room 201 a includes a kitchen area and a dining area, and a path 208 between the first physical location (a) and the second physical location (b) covers locations within the kitchen area and dining area where one or more listeners may experience audio playback during regular use of the playback device 210 a.

In some examples, movement of the network device 230 between the first physical location (a) and the second physical location (b) may be performed by a user. In one case, a graphical display of the network device 230 may provide an indication to move the network device 230 within the room 201 a. For instance, the graphical display may display text, such as “While audio is playing, please move the network device through locations within the playback zone where you or others may enjoy music.” Other examples are also possible.

The network device 230 determines a multi-location acoustic response of the room 201 a. To facilitate this, while the network device 230 is moving between physical locations within the room 201 a, the network device 230 captures audio data representing reflections of the audio content output by the playback device 210 a in the room 201 a. For instance, the network device 230 may be a mobile device with a built-in microphone (e.g., microphone(s) 115 of network microphone device 120 a), and the network device 230 may use the built-in microphone to capture the audio data representing reflections of the audio content at multiple locations within the room 201 a.

The multi-location acoustic response is an acoustic response of the room 201 a based on the detected audio data representing reflections of the audio content at multiple locations in the room 201 a, such as at the first physical location (a) and the second physical location (b). The multi-location acoustic response may be represented as a spectral response, spatial response, or temporal response, among others. The spectral response may be an indication of how volume of audio sound captured by the microphone varies with frequency within the room 201 a.

A power spectral density is an example representation of the spectral response. The spatial response may indicate how the volume of the audio sound captured by the microphone varies with direction and/or spatial position in the room 201 a. The temporal response may be an indication of how audio sound played by the playback device 210 a, e.g., an impulse sound or tone played by the playback device 210 a, changes within the room 201 a. The change may be characterized as a reverberation, delay, decay, or phase change of the audio sound.

The responses may be represented in various forms. For instance, the spatial response and temporal responses may be represented as room averages. Additionally, or alternatively, the multi-location acoustic response may be represented as a set of impulse responses or bi-quad filter coefficients representative of the acoustic response, among others. Values of the multi-location acoustic response may be represented in vector or matrix form.

Audio played by the playback device 210 a is adjusted based on the multi-location acoustic response of the room 201 a so as to offset or otherwise account for acoustics of the room 201 a indicated by the multi-location acoustic response. In particular, the multi-location acoustic response is used to identify calibration settings, which may include determining an audio processing algorithm. U.S. Pat. No. 9,706,323, incorporated by reference above, discloses various audio processing algorithms, which are contemplated herein.

In some examples, determining the audio processing algorithm involves determining an audio processing algorithm that, when applied to the playback device 210 a, causes audio content output by the playback device 210 a in the room 201 a to have a target frequency response. For instance, determining the audio processing algorithm may involve determining frequency responses at the multiple locations traversed by the network device while moving within the room 201 a and determining an audio processing algorithm that adjusts the frequency responses at those locations to more closely reflect target frequency responses. In one example, if one or more of the determined frequency responses has a particular audio frequency that is more attenuated than other frequencies, then determining the audio processing algorithm may involve determining an audio processing algorithm that increases amplification at the particular audio frequency. Other examples are possible as well.

In some examples, the audio processing algorithm takes the form of a filter or equalization. The filter or equalization may be applied by the playback device 210 a (e.g., via audio processing components 112 g). Alternatively, the filter or equalization may be applied by another playback device, the computing device 206, and/or the network device 230, which then provides the processed audio content to the playback device 210 a for output. The filter or equalization may be applied to audio content played by the playback device 210 a until such time that the filter or equalization is changed or is no longer valid for the room 201 a.

The audio processing algorithm may be stored in a database of the computing device 206 or may be calculated dynamically. For instance, in some examples, the network device 230 sends to the computing device 206 the detected audio data representing reflections of the audio content at multiple locations in the room 201 a, and receives, from the computing device 206, the audio processing algorithm after the computing device 206 has determined the audio processing algorithm. In other examples, the network device 230 determines the audio processing algorithm based on the detected audio data representing reflections of the audio content at multiple locations in the room 201 a.

Further, while the network device 230 captures audio data at multiple locations in the room 201 a for determining the multi-location acoustic response of the room 201 a, the playback device 210 a concurrently captures audio data at a stationary location for determining a localized acoustic response of the room 201 a. To facilitate this, the playback device 210 a may have one or more microphones, which may be fixed in location. For example, the one or more microphones may be co-located in or on the playback device 210 a (e.g., mounted in a housing of the playback device) or be co-located in or on an NMD proximate to the playback device 210 a. Additionally, the one or more microphones may be oriented in one or more directions. The one or more microphones detect audio data representing reflections of the audio content output by the playback device 210 a in the room 201 a, and this detected audio data is used to determine the localized acoustic response of the room 201 a.

The localized acoustic response is an acoustic response of the room 201 a based on the detected audio data representing reflections of the audio content at a stationary location in the room. The stationary location may be at the one or more microphones located on or proximate to the playback device 210 a, but could also be at the microphone of an NMD or a controller device proximate to the playback device 210 a.

The localized acoustic response may be represented as a spectral response, spatial response, or temporal response, among others. The spectral response may be an indication of how volume of audio sound captured by the microphone varies with frequency within the room 201 a. A power spectral density is an example representation of the spectral response. The spatial response may indicate how the volume of the audio sound captured by the microphone varies with direction and/or spatial position in the room 201 a. The temporal response may be an indication of how audio sound played by the playback device 210 a, e.g., an impulse sound or tone played by the playback device 210 a, changes within the room 201 a. The change may be characterized as a reverberation, delay, decay, or phase change of the audio sound. The spatial response and temporal response may be represented as averages in some instances. Additionally, or alternatively, the localized acoustic response may be represented as a set of impulse responses or bi-quad filter coefficients representative of the acoustic response, among others. Values of the localized acoustic response may be represented in vector or matrix form.

Once the multi-location calibration settings for the playback device 210 a and the localized acoustic response of the room 201 a are determined, this data is then provided to a computing device, such as computing device 206, for storage in a database. For instance, the network device 230 may send the determined multi-location calibration settings to the computing device 206, and the playback device 210 a may send the localized acoustic response of the room 201 a to the computing device 206. In other examples, the network device 230 or the playback device 210 a sends both the determined multi-location calibration settings and the localized acoustic response of the room 201 a to the computing device 206. Other examples are possible as well.

FIG. 2B depicts a representation of an example database 250 a for storing both the determined multi-location calibration settings for the playback device 210 a and the localized acoustic response of the room 201 a.

The database 250 a may be stored on a computing device, such as computing device 206, located remotely from the playback device 210 a and/or from the network device 230, or the database 250 a may be stored on the playback device 210 a and/or the network device 230. The database 250 a includes a number of records, and each record includes data representing multi-location calibrations settings (identified as “settings 1” through “settings 5”) for various playback devices as well as localized room responses (identified as “response 1A” through “response 5A”), and multi-location acoustic responses (identified as “response 1B through “response 5B), associated with the multi-location calibration settings. For the purpose of illustration, the database 250 a only depicts five records (numbered 1-5), but in practice should include many more than five records to improve the accuracy of the calibration processes described in further detail below.

When the computing device 206 receives data representing the multi-location calibration settings for the playback device 210 a and data representing the localized acoustic response of the room 201 a, the computing device 206 stores the received data in a record of the database 250 a. As an example, the computing device 206 stores the received data in record #1 of the database 250 a, such that “response 1” includes data representing the localized acoustic response of the room 201 a, and “settings 1” includes data representing the multi-location calibration settings for the playback device 210 a. In some cases, the database 250 a also includes data representing respective multi-location acoustic responses associated with the localized acoustic responses and the corresponding multi-location calibration settings. For instance, if record #1 of database 250 a corresponds to playback device 210 a, then “response 1” may include data representing both the localized acoustic response of the room 201 a and the multi-location acoustic response of the room 201 a.

As indicated above, each record of the database 250 a corresponds to a historical playback device calibration process in which a particular playback device was calibrated by determining calibration settings based on a multi-location acoustic response, as described above in connection with FIG. 2A. The calibration processes are “historical” in the sense that they relate to multi-location calibration settings and localized acoustic responses determined for rooms with various types of acoustic characteristics previously determined and stored in the database 250 a. As additional iterations of the calibration process are performed, the resulting multi-location calibration settings and localized acoustic responses may be added to the database 250 a.

As shown in the database 250 a, the localized room response and the calibration settings based on the multi-location calibration are correlated. In operation, portable playback devices may leverage the historical multi-location calibration settings and localized acoustic responses stored in the database 250 a in order to self-calibrate to account for the acoustic responses of the rooms in which they are located. During calibration of a portable playback device, the portable playback device uses its internal microphone(s) to record its own audio output and determines an instant localized response. This instant localized response can be compared to the localized room responses to determine a similar localized room response (i.e., a response that most similar), and thereby identify corresponding calibration settings based on a multi-location calibration. The playback device then applies to itself the multi-location calibration settings stored in the database 250 a that are associated with the identified record.

Efficacy of the applied calibration settings is influenced by a degree of similarity between the identified stored acoustic response in the database 250 a and the determined acoustic response for the playback device being calibrated. In particular, if the acoustic responses are significantly similar or identical, then the applied calibration settings are more likely to accurately offset or otherwise account for an acoustic response of the room in which the playback device being calibrated is located (e.g., by achieving or approaching a target frequency response in the room, as described above). On the other hand, if the acoustic responses are relatively dissimilar, then the applied calibration settings are less likely to accurately account for an acoustic response of the room in which the playback device being calibrated is located. Accordingly, populating the database 250 a with records corresponding to a significantly large number of historical calibration processes may be desirable so as to increase the likelihood of the database 250 a including acoustic response data similar to an acoustic response of the room of the playback device presently being calibrated.

As further shown, in some examples, the database 250 a includes data identifying a type of a playback device associate with each record. Playback device “type” refers to a model and/or revision of a model, as well as different models that are designed to produce similar audio output (e.g., playback devices with similar components), among other examples. The type of the playback device may be indicated when providing the calibration settings and room response data to the database 250 a. As an example, in addition to the network device 230 and/or the playback device 210 a sending data representing the multi-location calibration settings for the playback device 210 a and data representing the localized acoustic response of the room 201 a to the computing device 206, the network device 230 and/or the playback device 210 a also sends data representing a type of the playback device 210 a to the computing device. Examples of playback device types offered by Sonos, Inc. include, by way of illustration, various models of playback devices such as a “SONOS ONE,” “PLAY:1,” “PLAY:3,” “PLAY:5,” “PLAYBAR,” “PLAYBASE,” “CONNECT:AMP,” “CONNECT,” and “SUB,” among others.

In some examples, the data identifying the type of the playback device additionally or alternatively includes data identifying a configuration of the playback device. For instance, as described above in connection with FIG. 1E, a playback device may be a bonded or paired playback device configured to process and reproduce sound differently than an unbonded or unpaired playback device. Accordingly, in some examples, the data identifying the type of the playback device 210 a includes data identifying whether the playback device 210 a is in a bonded or paired configuration.

By storing in the database 250 a data identifying the type of the playback device, the database 250 a may be more quickly searched by filtering data based on playback device type, as described in further detail below. However, in some examples, the database 250 a does not include data identifying the device type of the playback device associated with each record.

In some implementations, calibrations settings for a first type of playback device may be used for a second type of playback device, provided that a model is created to translate from the first type to the second type. The model may include a transfer function that transfers a response of a first type of playback device to a response of a second type of playback device. Such models may be determined by comparing responses of the two types of playback devices in an anechoic chamber and determining a transfer function that translates between the two responses.

FIG. 2C depicts an example environment in which a playback device 210 b leverages the database 250 a to perform a self-calibration process without determining a multi-location acoustic response of its room 201 b.

In one example, the self-calibration of the playback device 210 b may be initiated when the playback device 210 b is being set up for the first time in the room 201 b, when the playback device 210 b first outputs music or some other audio content, or if the playback device 210 b has been moved to a new location. For instance, if the playback device 210 b is moved to a new location, calibration of the playback device 210 b may be initiated based on a detection of the movement (e.g., via a global positioning system (GPS), one or more accelerometers, or wireless signal strength variations), or based on a user input indicating that the playback device 210 b has moved to a new location (e.g., a change in playback zone name associated with the playback device 210 b).

In another example, calibration of the playback device 210 b may be initiated via a controller device, such as the controller device 130 a depicted in FIG. 1H. For instance, a user may access a controller interface for the playback device 210 b to initiate calibration of the playback device 210 b. In one case, the user may access the controller interface, and select the playback device 210 b (or a group of playback devices that includes the playback device 210 b) for calibration. In some cases, a calibration interface may be provided as part of a playback device controller interface to allow a user to initiate playback device calibration. Other examples are also possible.

Further, in some examples, calibration of the playback device 210 b is initiated periodically, or after a threshold amount of time has elapsed after a previous calibration, in order to account for changes to the environment of the playback device 210 b. For instance, a user may change a layout of the room 201 b (e.g., by adding, removing, or rearranging furniture), thereby altering the acoustic response of the room 201 b. As a result, any calibration settings applied to the playback device 210 b before the room 201 b is altered may have a reduced efficacy of accounting for, or offsetting, the altered acoustic response of the room 201 b. Initiating calibration of the playback device 210 b periodically, or after a threshold amount of time has elapsed after a previous calibration, can help address this issue by updating the calibration settings at a later time (i.e., after the room 201 b is altered) so that the calibration settings applied to the playback device 210 b are based on the altered acoustic response of the room 201 b.

Additionally, because calibration of the playback device 210 b involves accessing and retrieving calibration settings from the database 250 a, as described in further detail below, initiating calibration of the playback device 210 b periodically, or after a threshold amount of time has elapsed after a previous calibration, may further improve a listening experience in the room 201 b by accounting for changes to the database 250 a. For instance, as users continue to calibrate various playback devices in various rooms, the database 250 a continues to be updated with additional acoustic room responses and corresponding calibration settings. As such, a newly added acoustic response (i.e., an acoustic response that is added to the database 250 a after the playback device 210 b has already been calibrated) may more closely resemble the acoustic response of the room 201 b.

Thus, by initiating calibration of the playback device 210 b periodically, or after a threshold amount of time has elapsed after a previous calibration, the calibration settings corresponding to the newly added acoustic response may be applied to the playback device 210 b. Accordingly, in some examples, the playback device 210 b determines that at least a threshold amount of time has elapsed after the playback device 210 b has been calibrated, and, responsive to making such a determination, the playback device 210 b initiates a calibration process, such as the calibration processes described below.

When performing the calibration process, the playback device 210 b outputs audio content and determines a localized acoustic response of its room 201 b similarly to how playback device 210 a determined a localized acoustic response of room 201 a. For instance, the playback device 210 b outputs audio content, which may include music or one or more predefined tones, captures audio data representing reflections of the audio content within the room 201 b, and determines the localized acoustic response based on the captured audio data.

Causing the playback device 210 b to output spectrally rich audio content during the calibration process may yield a more accurate localized acoustic response of the room 201 b. Thus, in examples where the audio content includes predefined tones, the playback device 210 b may output predefined tones over a range of frequencies for determining the localized acoustic response of the room 201 b. And in examples where the audio content includes music, such as music played during normal use of the playback device 210 b, the playback device 210 b may determine the localized acoustic response based on audio data that is captured over an extended period of time.

For instance, as the playback device 210 b outputs music, the playback device 210 b may continue to capture audio data representing reflections of the output music within the room 201 b until a threshold amount of data at a threshold amount of frequencies is captured. Depending on the spectral content of the output music, the playback device 210 b may capture the reflected audio data over the course of multiple songs, for instance, in order for the playback device 210 b to have captured the threshold amount of data at the threshold amount of frequencies. In this manner, the playback device 210 b gradually learns the localized acoustic response of the room 201 b, and once a threshold confidence in understanding of the localized acoustic response of the room 201 b is met, then the playback device 210 b uses the localized acoustic response of the room 201 b to determine calibration settings for the playback device 210 b, as described in further detail below.

While outputting the audio content, the playback device 210 b uses one or more stationary microphones, which may be disposed in or on a housing of the playback device 210 b or may be co-located in or on an NMD proximate to the playback device 210 b, to capture audio data representing reflections of the audio content in the room 201 b. The playback device 210 b then uses the captured audio data to determine the localized acoustic response of the room 201 b. In line with the discussion above, the localized acoustic response may include a spectral response, spatial response, or temporal response, among others, and the localized acoustic response may be represented in vector or matrix form.

In some embodiments, determining the localized acoustic response of the room 201 b involves accounting for a self-response of the playback device 210 b or of a microphone of the playback device 210 b, for example, by processing the captured audio data representing reflections of the audio content in the room 201 b so that the captured audio data reduces or excludes the playback device’s native influence on the audio reflections.

In one example, the self-response of the playback device 210 b is determined in an anechoic chamber, or is otherwise known based on a self-response of a similar playback device being determined in an anechoic chamber. In the anechoic chamber, audio content output by the playback device 210 b is inhibited from reflecting back toward the playback device 210 b, so that audio captured by a microphone of the playback device 210 b is indicative of the self-response of the playback device 210 b or of the microphone of the playback device 210 b. Knowing the self-response of the playback device 210 b or of the microphone of the playback device 210 b, the playback device 210 b offsets such a self-response from the captured audio data representing reflections of the first audio content when determining the localized acoustic response of the room 201 b.

Once the localized acoustic response of the room 201 b is known, the playback device 210 b accesses the database 250 a to determine a set of calibration settings to account for the acoustic response of the room 201 b. More specifically, the playback device 210 b determines a recorded and stored localized acoustic response recorded during a previous multi-location calibration which is within a threshold similarity (e.g., most similar to) the localized acoustic response of the room 201 b. For example, the playback device 210 b establishes a connection with the computing device 206 and with the database 250 a of the computing device 206, and the playback device 210 b queries the database 250 a for a stored acoustic room response that corresponds to the determined localized acoustic response of the room 201 b.

In some examples, querying the database 250 a involves mapping the determined localized acoustic response of the room 201 b to a particular stored acoustic room response in the database 250 a that satisfies a threshold similarity to the localized acoustic response of the room 201 b. This mapping may involve comparing values of the localized acoustic response to values of the stored localized acoustic room responses and determining which of the stored localized acoustic room responses are similar to the instant localized acoustic response. For example, in implementations where the acoustic responses are represented as vectors, the mapping may involve determining distances between the localized acoustic response vector and the stored acoustic response vectors. In such a scenario, the stored acoustic response vector having the smallest distance from the localized acoustic response vector of the room 201 b may be identified as satisfying the threshold similarity. In some examples, one or more values of the localized acoustic response of the room 201 b may be averaged and compared to corresponding averaged values of the stored acoustic responses of the database 250 a. In such a scenario, the stored acoustic response having averaged values closest to the averaged values of the localized acoustic response vector of the room 201 b may be identified as satisfying the threshold similarity. Other examples are possible as well.

As shown, the room 201 b depicted in FIG. 2C and the room 201 a depicted in FIG. 2A are similarly shaped and have similar layouts. Further, the playback device 210 b and the playback device 210 a are arranged in similar positions in their respective rooms. As such, when the localized room response determined by playback device 210 b for room 201 b is compared to the room responses stored in the database 250 a, the computing device 206 may determine that the localized room response determined by playback device 210 a for room 201 a has at least a threshold similarity to the localized room response determined by playback device 210 b for room 201 b.

In some examples, querying the database 250 a involves querying only a portion of the database 250 a. For instance, as noted above, the database 250 a may identify a type or configuration of playback device for which each record of the database 250 a is generated. Playback devices of the same type or configuration may be more likely to have similar room responses and may be more likely to have compatible calibration settings. Accordingly, in some embodiments, when the playback device 210 b queries the database 250 a for comparing the localized acoustic response of the room 201 b to the stored room responses of the database 250 a, the playback device 210 b might only compare the localized acoustic response of the room 201 b to stored room responses associated with playback devices of the same type or configuration as the playback device 210 b.

Once a stored acoustic room response of the database 250 a is determined to be threshold similar to the localized acoustic response of the room 201 b, then the playback device 210 b identifies a set of calibration settings associated with the threshold similar stored acoustic room response. For instance, as shown in FIG. 2B, each stored acoustic room response is included as part of a record that also includes a set of calibration settings designed to account for the room response. As such, the playback device 210 b retrieves, or otherwise obtains from the database 250 a, the set of calibration settings that share a record with the threshold similar stored acoustic room response and applies the set of calibration settings to itself. Alternatively, the playback device 201 b may determine (i.e. calculate) a set of calibration settings based on a target frequency curve and the threshold similar stored acoustic room response.

After applying the obtained calibration settings to itself, the playback device 210 b outputs, via its one or more transducers, second audio content using the applied calibration settings. Even though the applied calibration settings were determined for a different playback device calibrated in a different room, the localized acoustic response of the room 201 b is similar enough to the stored acoustic response that the second audio content is output in a manner that at least partially accounts for the acoustics of the room 201 b. For instance, with the applied calibration settings, the second audio content output by the playback device 210 b may have a frequency response, at one or more locations in the room 201 b, that is closer to a target frequency response than the first audio content.

IV. Example Systems and Methods for Calibrating a Portable Playback Device

FIG. 2D depicts example environments in which a portable playback device 210 c performs playback device calibration upon changing conditions, such as movement to a new location or passage of time. The portable playback device 210 c may be similar to any of the playback devices 110 depicted in FIGS. 1A-1E and 1G, and the network device 230 may be similar to any of the NMDs 120 or controllers 130 depicted in FIGS. 1A-1B and 1F-1H. In contrast with the playback devices 110, the portable playback device 210 c may be configured for portable use. As such, the portable playback device 210 c may include one or more batteries to power the portable playback device 210 c while disconnected from wall power. Further, the components of the portable playback device 210 c may be configured to facilitate portable use such as by implementing certain processors, amplifiers, and/or transducers to balance audio output levels and battery life. Yet further, a housing of the portable playback device 210 c may be configured to facilitate portable use such as by including or incorporating a carrying handle or the like.

Given that the portable playback device 210 c is configured for portable operation, during regular use, a user may be expected to relocate the portable playback device 210 c relatively frequently. For example, at various times a user may move portable playback device 210 c to locations 252 a, 252 b, and 252 c in rooms 201 c, 201 d, and 201 e, respectively. By way of example, room 201 c may be a kitchen, room 201 d may be a family room, and room 201 e may be a patio or other outdoor area. Localized acoustic responses vary between rooms 201 c, 201 d, and 201 e and self-calibration at each location is desirable. The portable playback device 210 c might not consistently or reliably have access to database 250 a and/or computing device 206, as the portable playback device 210 c may be located out of Wi-Fi range or may disable its network interface(s) to lower battery use. As such, in some embodiments, the portable playback device 210 c may include a locally stored database 250 b (as shown in FIG. 2E) to perform self-calibration on the portable playback device 210 c without accessing a remote database.

Additionally or alternatively, the playback device 210 c may leverage both a remote database, such as database 250 a, and a local database, such as database 250 b, during various calibrations. More specifically, in some embodiments, the playback device 210 c may access a remote database, such as database 250 a, when said access is available. For example, the playback device 210 c may perform calibration by accessing the remote database 250 a when the playback device is within Wi-Fi range and by accessing the local database 250 b when the playback device is outside of Wi-Fi range.

In some embodiments, portable playback devices may perform calibration using a multi-location acoustic response of a room by way of methods disclosed herein and incorporated by reference. In some embodiments, portable playback devices may leverage a database (e.g., 250 a or 250 b) used to perform self-calibration process without determining a multi-location acoustic response of its room by way of methods disclosed herein and incorporated by reference. Further, some portable playback devices may be configured to perform calibration by way of using a multi-location acoustic response of a room and self-calibration process without determining a multi-location acoustic response of its room. As such, a variety of calibration initiation techniques may be employed on portable playback devices to account for various device capabilities and environments.

A. Calibration Initiation

The portable playback device 210 c calibration and/or self-calibration process may be initiated at various times and/or in various ways. In one example, calibration and/or self-calibration of the portable playback device 210 c may be initiated when the portable playback device 210 c is being set up for the first time, for example, in the room 201 c and/or when the portable playback device 210 c first outputs music or some other audio content, as described in any manner disclosed herein. In another example embodiment, the portable playback device 210 c may initiate calibration and/or self-calibration when the power is turned on and/or audio content begins playing.

To account for the movement, and therefore changing conditions, of the portable playback device 210 c, a variety of self-calibration initiation techniques may be employed. In some example embodiments, the playback device 210 c initiates self-calibration based on movement to a new location. By way of example, a user may move the portable playback device 210 c from room 201 c to room 201 d. The portable playback device 210 c may initiate self-calibration once the portable playback device 210 c is placed in the new location 252 b. Similarly, the portable playback device 210 c may stall or suspend any self-calibration upon indication of movement, as self-calibration while the portable playback device 210 c is in transit is unnecessary and would result in an inaccurate acoustic room response.

In these examples, the portable playback device 210 c may be configured to detect movement of the portable playback device 210 c by way of, for example, one or more accelerometers, or other suitable motion detection devices (e.g., via a GPS or wireless signal strength variations). An accelerometer, or other motion detection device, is configured to collect and output data indicative of movement by the portable playback device 210 c. The portable playback device 210 c may determine whether to initiate self-calibration and/or suspend self-calibration based on movement data from the accelerometer. More specifically, the portable playback device 210 c may suspend self-calibration upon receiving an indication from the accelerometer that the portable playback device 210 c is in motion. Conversely, the portable playback device 210 c may initiate self-calibration upon receiving an indication from the accelerometer that the portable playback device 210 c is stationary for a predetermined duration of time (e.g., 5 seconds, 10 seconds). Further, the playback device 210 c may not initiate calibration unless and/or until the playback device 210 c is in use (i.e., outputting audio content).

In some example embodiments, self-calibration of the portable playback device 210 c may only be initiated upon placement of the portable playback device 210 c (i.e., self-calibration initiates when the portable playback device 210 c is set down on a surface or playback device base (as described below)). In these examples, the portable playback device 210 c does not initiate self-calibration until the portable playback device 210 c has been moved and set down and is stationary.

In a different example scenario, a user may move the portable playback device 210 c while in use (i.e., outputting audio content) but between self-calibration periods (i.e., the portable playback device 210 c is not actively performing self-calibration). The portable playback device 210 c may detect the motion by way of motion data from the accelerometer. In response to receiving the motion data, the portable playback device 210 c may delay initiation of self-calibration until receiving data indicating the portable playback device 210 c is stationary. Once the portable playback device 210 c is stationary for a period of time (e.g., 2 seconds) the portable playback device 210 c may initiate self-calibration and continue, for example, periodically thereafter.

Similarly, in another example scenario, a user may move the portable playback device 210 c while in use and while the portable playback device 210 c is performing self-calibration. In response to receiving data from the accelerometer indicating the portable playback device 210 c is in motion, the portable playback device 210 c may suspend calibration until the portable playback device 210 c is stationary again. In some examples, the portable playback device 210 c may initiate self-calibration once the portable playback device 210 c is stationary for a period of time (e.g., 2 seconds). The portable playback device 210 c may continue initiating self-calibration, for example, periodically thereafter. Similar methods may be utilized for other suitable motion detection devices, such as a GPS or gyroscope.

In some embodiments, while the portable playback device 210 c is in motion, the most-recent determined audio calibration settings may be applied to the audio content. Alternatively, while the portable playback device 210 c is in motion, standard audio calibration settings may be applied, such as a factory default setting. In another example, while the portable playback device 210 c is in motion, the portable playback device 210 c may apply stored set of audio calibration settings for use when the portable playback device 210 c is in motion. Many other examples are possible. To avoid an abrupt change in audio calibration settings, such as when portable playback device 210 c is picked up and factory default audio calibration settings are applied, audio calibration settings may be applied gradually (e.g., over a period of 5 seconds).

Further, in some embodiments, any calibration data stored on the portable playback device 210 c or applied to the audio content may be erased from the portable playback device 210 c once it is moved or picked up. By deleting calibration data, data storage and/or processing cycles may be freed up.

Additionally or alternatively, portable playback device 210 c may be compatible with one or more playback device bases. A playback device base may include, for example, device charging systems, a base identifier (i.e., distinguishes that playback device base from other playback device bases), and a control system including one or more processors and a memory. Additional details regarding playback device bases may be found, for example, in U.S. Pat. No. 9,544,701, which was incorporated by reference above.

In some embodiments, a single playback device may be compatible with a number of playback device bases. Similarly, a playback device base may be compatible with a number of playback devices. By way of example, there may be a first, second, and third playback device base at locations 252 a, 252 b, and 252 c, respectively. In this example, the portable playback device 210 c may be compatible with all three playback device bases. In these examples, the portable playback device 210 c may initiate calibration and/or self-calibration once the portable playback device 210 c is placed on any of the playback device bases.

In some embodiments, the portable playback device 210 c, the playback device base, and/or the computing device 206 may store the determined acoustic response once the portable playback device 210 c has been calibrated at a particular base. For example, the portable playback device 210 c may be placed on the playback device base at location 252 b and initiate self-calibration. Once the self-calibration is complete, the portable playback device 210 c, the playback device base, and/or the computing device 206 may store the determined audio calibration settings. More specifically, in some embodiments, the portable playback device 210 c may store the determined acoustic response locally on the device with the corresponding playback device base identifier. This is desirable for future use, as the determined audio calibration settings can be readily be retrieved and applied to the portable playback device 210 c once the portable playback device 210 c is placed on the playback device base at a later time. Similarly, the determined audio calibration settings may be transmitted to a remote computing device, such as computing device 206, to be retrieved at a later time.

Further, the determined acoustic response may be stored locally on the playback device base or remotely on the computing device 206 for other playback devices placed on the playback device base at a later time. For example, a playback device, other than portable playback device 210 c, may be compatible with and placed on the playback device base at location 252 b. The newly placed playback device may retrieve and apply stored audio calibration settings for example, from the playback device base or the remote computing device 206.

Additionally, in some examples, a playback device base may be compatible with more than one type or model of playback device. In these examples, the playback device base and/or remote computing device 206 may store calibration settings specific to the different types of playback devices. For example, a playback device base may be compatible with portable playback device 210 c and a “SONOS ONE” playback device. The playback device base and/or computing device 206 may store audio calibration settings corresponding to the type of playback device, such that audio calibrations settings specific to the type of device may be readily retrieved and applied to the audio content (e.g., “SONOS ONE” playback device calibration settings are applied to any “SONOS ONE” playback devices placed on the playback device base at a particular location). In another example embodiment, the playback device base and/or remote computing device 206 may store acoustic responses which are independent of device type. For example, the playback device 210 c may retrieve and apply audio calibration settings corresponding to an acoustic response previously determined by a different type of playback device and stored on the playback device base and/or remote computing device 206.

In some example embodiments, the playback device base excludes a playback device base identifier. In these examples, the playback device 210 c may perform calibration and/or self-calibration upon placement on the playback device base to identify the particular playback device base. For example, the playback device 210 c may identify that it has been placed on a playback device base and match the same or similar acoustic response with a determined acoustic response from a previously performed calibration and/or self-calibration stored on the playback device 210 c and retrieve and apply the audio calibration settings selected in the previous calibration.

Receiving the same or similar response indicates that the playback device 210 c may be on the same playback device base as when the matching or similar acoustic response was previously recorded. In some examples the playback device 210 c may store the acoustic responses and determined audio calibration setting in association with the particular playback device. In some examples, the matching or similar previously determined acoustic response may have been determined using the multi-location calibration techniques, whereas the more recent acoustic response was determined without using the multi-location calibration techniques. In these examples, the playback device 210 c may apply the audio settings corresponding to the determined multi-location acoustic response, as this room response may be more accurate.

Alternatively, in examples where the playback device 210 c does not identify a matching acoustic response, the playback device 210 c may initiate or continue calibration and/or self-calibration according to any of the calibration initiation techniques described herein.

In another example, calibration and/or self-calibration of the portable playback device 210 c may be initiated via a controller device, such as the controller device 130 a depicted in FIG. 1H. For instance, a user may access a controller interface for the portable playback device 210 c to initiate calibration of the playback device 210 c. In one case, the user may access the controller interface, and select the portable playback device 210 c (or a group of playback devices that includes the portable playback device 210 c) for calibration. In some cases, a calibration interface may be provided as part of a playback device controller interface to allow a user to initiate playback device calibration. Additionally, self-calibration may be initiated based on a user input indicating that the portable playback device 210 c has moved to a new location (e.g., a change in playback zone name associated with the playback device 210 c). Other examples are also possible.

In another example, calibration of the portable playback device 210 c may be initiated by a user via voice input or a voice command. In these examples, the portable playback device 210 c may be an NMD, such as NMD 120 a. The user may say a command, such as “calibrate” or “start calibration”. Upon receipt and processing of the command, the portable playback device 210 c may initiate calibration. Many other calibration initiation processing commands are possible.

Similarly, in some embodiments, the portable playback device 210 c may initiate self-calibration in response to receiving an instruction or command to play audio content. For example, a user may issue a command by way of, for example, a controller device 130 a or voice command to play music on the portable playback device 210 c. Once the music begins playing, portable playback device 210 c may initiate self-calibration.

In some examples, a user may wish to deactivate automatic or repetitive (e.g., periodic, as described below) self-calibration. In these examples, the user may deactivate or stall calibration by way of a controller device 130 a or a voice command, as described above. For example, the user may toggle an automatic calibration function on or off by way of a user interface on the controller device 130 a. This may be desirable to save battery power, as, in some implementations, the calibration is computationally intensive and involves significant battery usage. This may also be desirable to accommodate user preference. Self-calibration relies on enablement of one or more microphones on the portable playback device 210 c, which may also be utilized for voice-commands, as described above. As such, the user may toggle off the automatic calibration of the portable playback device 210 c due to a preference to keep the one or more microphones disabled.

Further, in some examples, self-calibration of the playback device 210 b is initiated periodically, or after a threshold amount of time has elapsed after a previous calibration, in order to account for changes to the environment or changes in the location of the playback device 210 c.

In some embodiments, the portable playback device 210 c may initiate self-calibration periodically while the portable playback device 210 c is in use (i.e., outputting audio content). For example, the time period between self-calibration cycles may be between 10 seconds and 30 seconds. In other examples, the portable playback device 210 c may initiate self-calibration every 30 minutes. Many other examples are possible.

In some examples, the portable playback device 210 c is playing audio content when the predetermined duration of time has passed. Because playing audio content is necessary for self-calibration, the portable playback device 210 c may stall or suspend the calibration initiation until the portable playback device 210 c begins outputting audio content (e.g., when a user issues a command to play music on the portable playback device 210 c, as described above). Further, as described above, calibration may continue over a period of time until enough acoustic response data is recorded and collected. In some examples, the period between calibrations is measured from the time calibration is completed. In other examples, the period between calibrations is measured from the initiation of the calibration.

Receiving the same or similar acoustic response data indicates that the portable playback device 210 c has not moved since a previous self-calibration and therefore does not require further calibration until the portable playback device 210 c is relocated. As such, in some embodiments, periodic self-calibration initiation may slow (i.e., the time periods between self-calibration increase) or stop if the acoustic response data is the same or similar over a period of time.

For example, the portable playback device 210 c may be in use (i.e., outputting audio content) in location 252 a for an extended period without relocation. In this example, the portable playback device 210 c may periodically initiate self-calibration every 20 seconds. After receiving the same or similar acoustic response a number of times (e.g., 15 times), the portable playback device may increase the self-calibration initiation period to, for example, 40 seconds. The portable playback device 210 c may continue to increase the self-calibration initiation period upon repeatedly receiving the same or similar acoustic responses (e.g., 60 seconds, 80 seconds, etc.). In some embodiments, the portable playback device 210 c may even suspend self-calibration initiation until receiving some other prompt to perform calibration and/or self-calibration (e.g., receiving data indicating motion of the portable playback device 210 c, user instruction, etc.). This may be desirable to save battery power, as the self-calibration process is computationally intensive and involves a significant battery usage.

In some embodiments, periodic self-calibration initiation may be used in combination with other calibration and/or self-calibration initiation techniques, such as motion data based and/or playback device base calibration initiation. For example, the portable playback device 210 c may periodically initiate self-calibration. In one example scenario, a user may move the portable playback device 210 c while in use (i.e., outputting audio content) but between self-calibration periods. The portable playback device 210 c may detect the motion by way of motion data from the accelerometer. In response to receiving the motion data, the portable playback device 210 c may not initiate self-calibration until receiving data indicating the portable playback device 210 c is stationary. Once the portable playback device 210 c is stationary for a period of time (e.g., 10 seconds) the portable playback device 210 c may initiate self-calibration and continue thereafter periodically.

Similarly, in another example scenario, a user may move the portable playback device 210 c while in use and while the portable playback device is performing calibration and/or self-calibration. In response to receiving data from the accelerometer indicating the portable playback device 210 c is in motion, the portable playback device may suspend self-calibration until the portable playback device is stationary again. Once the portable playback device 210 c is stationary for a period of time (e.g., 10 seconds) the portable playback device 210 c may initiate self-calibration and continue thereafter periodically. Additionally or alternatively, the playback device 210 c may delete or discard the data collected via the microphone before the playback device 210 c began moving (i.e., the data from the interrupted/suspended calibration).

Additionally or alternatively, in some embodiments the portable playback device 210 c initiates self-calibration periodically while being used in conjunction with a playback device base to account for changing conditions in the environment of the portable playback device 210 c. In an example scenario, a user may remove the portable playback device 210 c from the playback device base at location 252 a while in use but between self-calibration periods. Once the portable playback device 210 c is removed from the playback device base, the portable playback device 210 c does not initiate self-calibration until receiving data indicating the portable playback device 210 c is stationary or placed on another playback device base (e.g., playback device base at location 252 b). Once the portable playback device 210 c is stationary for a period of time (e.g., 10 seconds) and/or is placed at another playback device base (e.g., playback device base at location 252 b), the portable playback device 210 c may initiate calibration and continue thereafter periodically.

Similarly, in an example scenario, a user may remove the portable playback device 210 c from the playback device base at location 252 a while outputting audio content and while the portable playback device 210 c is performing calibration. Once the portable playback device 210 c is removed from the playback device base, the portable playback device 210 c, may suspend self-calibration until the portable playback device is stationary again or placed on another playback device base (e.g., playback device base at location 252 b). Once the portable playback device 210 c is stationary for a period of time and/or is placed at another playback device base (e.g., playback device base at location 252 b), the portable playback device 210 c may initiate self-calibration and continue thereafter periodically.

These calibration and self-calibration initiation techniques may be used alone or in combination with any calibration techniques described herein.

B. Portable Playback Device Local Calibration and Local Calibration Database

As described above, in some embodiments, portable playback devices may perform calibration using a multi-location acoustic response of a room by way of methods disclosed herein. In some embodiments, portable playback devices may leverage a database (e.g., 250 a or 250 b) to perform self-calibration process without determining a multi-location acoustic response of its room by way of methods disclosed herein. Further, some portable playback devices may be configured to perform both calibration by way of using a multi-location acoustic response of a room and self-calibration process without determining a multi-location acoustic response of its room. Due to movement and relocation, portable playback device 210 c might not consistently or reliably have access to database 250 a and/or computing device 206. As such, in some embodiments, the portable playback device 210 c may include a locally stored database 250 b (as shown in FIG. 2E) to perform self-calibration on the portable playback device 210 c without accessing a remote database.

FIG. 2E depicts an example representation of database 250 a to be locally stored database 250 b for portable playback device 210 c. To account for the storage and computational capabilities of an individual portable playback device 210 c, the locally stored database 250 b may be a representation or generalization of the database 250 a stored on a remote computing device 206.

As described above, the database 250 a leveraged during some self-calibration is based on historical calibration settings 256 previously collected on other playback devices in which a particular playback device was calibrated by determining calibration settings based on a multi-location acoustic response. In some examples, the database 250 a includes historical calibration settings collected on many types of playback devices. In another example the database 250 a includes historical calibration settings collected specifically on a number of portable playback devices. These historical calibration settings for portable playback devices may be developed through concurrent multi-location acoustic responses and localized acoustic responses, as described above.

In some example embodiments, the locally stored database 250 b may include historical data points 256, or a representation thereof, from the entirety or a majority of database 250 a. In other example embodiments, the locally stored database 250 b may include historical data points 256, or a representation thereof, from calibration settings collected on portable playback devices. Alternatively, in some example embodiments, the locally stored database 250 b may include historical data points 256, or a representation thereof, from calibration settings collected on a limited number of types of playback devices which are similar in some way to portable playback devices. Many examples are possible.

In some example embodiments, the locally stored database 250 b is a generalization of database 250 a. One example of such a generalization or representation is a best fit line 254 of a frequency response. In these examples, the portable playback device 210 c may locally store the generalization (i.e., best fit line 254) data. Another example of a generalization or representation is a best fit line 254 of historical local responses corresponding to historical multi-location responses. While FIG. 2E illustrates a best fit line 254 along two axes, a best fit line 254 may be representative of a number of inputs in multi-dimensional space. This is desirable as a best fit line 254 requires much less memory and self-calibration may be much less computationally intensive. In these examples, the locally stored database 250 b may only include the best fit line(s) 254 rather than the individual historical data points 256. While FIG. 2E illustrates a single best fit line 254, locally stored database 250 b may include a number of best fit lines 254. Other examples of representations and generalizations are possible as well. Further, the portable playback device 210 c software updates may include updating database 250 b to include updated data, as more multi-location calibration settings and localized acoustic responses are added to database 250 a, as described above.

Self-calibration of portable playback devices may be similar to the methods of self-calibration of stationary playbacks described, herein. During self-calibration of a portable playback device 210 c, however, the portable playback device may leverage the locally stored database 250 b, rather than database 250 a.

For example, when performing the self-calibration process, the portable playback device 210 c outputs audio content and determines a localized acoustic response of its room 201 c similarly to how playback devices 210 a and 210 b determined a localized acoustic response of rooms 201 a and 201 b, respectively. For instance, the portable playback device 210 c outputs audio content, which may include music or one or more predefined tones, captures audio data representing reflections of the audio content within the room 201 c, and determines the localized acoustic response based on the captured audio data.

As described above, in examples where the portable playback device 210 c outputs music, the portable playback device 210 c may continue to capture audio data representing reflections of the output music within the room 201 c until a threshold amount of data at a threshold amount of frequencies is captured. Depending on the spectral content of the output music, the portable playback device 210 c may capture the reflected audio data over the course of multiple songs, for instance, in order for the portable playback device 210 c to have captured the threshold amount of data at the threshold amount of frequencies. In this manner, the portable playback device 210 c learns the localized acoustic response of the room 201 c, and once a threshold confidence in understanding of the localized acoustic response of the room 201 c is met, then the playback device 210 c uses the localized acoustic response of the room 201 c to determine calibration settings for the portable playback device 210 c utilizing the locally stored database 250 b, as described in further detail below.

While outputting the audio content, the portable playback device 210 c uses one or more stationary microphones, which may be disposed in or on a housing of the portable playback device 210 c or may be co-located in or on an NMD proximate to the portable playback device 210 c, to capture audio data representing reflections of the audio content in the room 201 c. The playback device 210 c then uses the captured audio data to determine the localized acoustic response of the room 201 c. As described above, the localized acoustic response may include a spectral response, spatial response, or temporal response, among others, and the localized acoustic response may be represented in vector or matrix form.

In some embodiments, determining the localized acoustic response of the room 201 c involves accounting for a self-response of the portable playback device 210 c or of a microphone of the portable playback device 210 c, for example, by processing the captured audio data representing reflections of the audio content in the room 201 c so that the captured audio data reduces or excludes the playback device’s native influence on the audio reflections.

In one example, the self-response of the portable playback device 210 c is determined in an anechoic chamber, or is otherwise known based on a self-response of a similar portable playback device being determined in an anechoic chamber. In the anechoic chamber, audio content output by the portable playback device 210 c is inhibited from reflecting back toward the portable playback device 210 c, so that audio captured by a microphone of the portable playback device 210 c is indicative of the self-response of the portable playback device 210 c or of the microphone of the portable playback device 210 c. Knowing the self-response of the portable playback device 210 c or of the microphone of the portable playback device 210 c, the portable playback device 210 c offsets such a self-response from the captured audio data representing reflections of the first audio content when determining the localized acoustic response of the room 201 c.

Further, in some example scenarios, the portable playback device 210 c may be in a very noisy environment, such as a social event or outdoors. As such, in some examples, the audio processing algorithm may include a noise classifier to filter out noise when performing calibration or self-calibration. The noise classifier may be applied by the playback device 210 c (e.g., via audio processing components 112 g). Additionally or alternatively, the portable playback device 210 c may apply a beam forming algorithm, such as a multichannel Weiner filter, to eliminate certain environmental noises (e.g., conversations in the foreground) when calibrating and/or self-calibrating the portable playback device 210 c.

Once the localized acoustic response of the room 201 c is known, the portable playback device 210 c accesses the locally stored database 250 b to determine a set of calibration settings to account for the acoustic response of the room 201 c. For example, the portable playback device 210 c queries the locally stored database 250 b for a stored best fit line 254 room response that corresponds to the determined localized acoustic response of the room 201 c.

In some examples, querying the locally stored database 250 b involves mapping the determined localized acoustic response of the room 201 c to a particular stored acoustic room response in the database locally stored database 250 b that satisfies a threshold similarity to the localized acoustic response of the room 201 c. More specifically, in some example embodiments, the playback device 210 c determines a recorded and stored localized acoustic response from a previous multi-location calibration which is within a threshold similarity (e.g., most similar to) the localized acoustic response of the room 201 b. This mapping may involve comparing values of the localized acoustic response to values of the stored acoustic room responses, or representations thereof according to the best fit line(s) 254, and determining which of the stored acoustic room responses are similar to the localized acoustic response. In some embodiments, the most similar stored acoustic room response is selected. Other examples are possible as well.

Once a stored acoustic room response of the locally stored database 250 b is selected to be threshold similar to the localized acoustic response of the room 201 c, then the portable playback device 210 c identifies a set of calibration settings associated with the threshold similar stored acoustic room response. For instance, as shown in FIG. 2E, the best fit line 254 associates room responses and audio calibration settings. As such, the portable playback device 210 c retrieves, or otherwise obtains from the locally stored database 250 b, the set of calibration settings associated with the similar stored acoustic room response and applies the set of calibration settings to itself.

Portable playback device 210 c may repeat this self-calibration process, or any other calibration process described herein, in any room or area (e.g., 201 d and/or 20 e) it is moved to according to any of the calibration initiation techniques described herein.

V. Example Methods

FIG. 3 shows an example embodiment of a method 300 for establishing a database of calibration settings for playback devices. The method 300 can be implemented by any of the playback devices disclosed and/or described herein, or any other playback device now known or later developed.

Various embodiments of the method 300 include one or more operations, functions, and actions illustrated by blocks 302 through 316. Although the blocks are illustrated in sequential order, these blocks may also be performed in parallel, and/or in a different order than the order disclosed and described herein. Also, the various blocks may be combined into fewer blocks, divided into additional blocks, and/or removed based upon a desired implementation.

In addition, for the method 300 and for other processes and methods disclosed herein, the flowcharts show functionality and operation of one possible implementation of some embodiments. In this regard, each block may represent a module, a segment, or a portion of program code, which includes one or more instructions executable by one or more processors for implementing specific logical functions or steps in the process. The program code may be stored on any type of computer readable medium, for example, such as a storage device including a disk or hard drive. The computer readable medium may include non-transitory computer readable media, for example, such as tangible, non-transitory computer-readable media that stores data for short periods of time like register memory, processor cache, and Random Access Memory (RAM). The computer readable medium may also include non-transitory media, such as secondary or persistent long term storage, like read only memory (ROM), optical or magnetic disks, compact-disc read only memory (CD-ROM), for example. The computer readable media may also be any other volatile or non-volatile storage systems. The computer readable medium may be considered a computer readable storage medium, for example, or a tangible storage device. In addition, for the method 300 and for other processes and methods disclosed herein, each block in FIG. 3 may represent circuitry that is wired to perform the specific logical functions in the process.

The method 300 involves calibrating a portable playback device by way of a locally stored acoustic response database.

The method 300 begins at a block 302, which involves storing, via a playback device, an acoustic response database comprising a plurality of sets of stored audio calibration settings. Each set of stored audio calibration settings is associated with a respective stored acoustic area response of a plurality of stored acoustic area responses. Example acoustic response databases include the database 250 a (FIG. 2B) and the database 250 b (FIG. 2E).

At the block 304, the method 300 involves determining that the playback device is to perform an equalization calibration of the playback device. In some embodiments, the block 304 may further involve, receiving from the accelerometer, data indicating the playback device is stationary for a predetermined duration of time. In response to detecting that the playback device is stationary for the predetermined duration of time, the playback device initiates the equalization calibration of the playback device.

In some embodiments, the block 304 may additionally involve performing the equalization calibration periodically over a first time period. Further, the playback device may receive, from the accelerometer, data indicating the playback device is stationary for a predetermined duration of time. In response to detecting that the playback device is stationary over the predetermined duration of time, the playback device performs the equalization calibration periodically over a second time period. The second time period is longer than the first time period.

In some embodiments, the block 304 may additionally involve receiving an instruction to play audio content. In response to the instruction to play audio content, the playback device plays the audio content and initiates the equalization calibration of the playback device.

In some embodiments, the block 304 may additionally involve excluding captured audio data representing noise in the area in which the playback device is located.

At block 306, the method 300 involves outputting, via the speaker, audio content.

At block 308, the method 300 involves initiating the equalization calibration. In some embodiments, block 308 may additionally involve performing the equalization calibration periodically, wherein a time period between the equalization calibration is between 10 seconds and 30 seconds.

At block 310, the method 300 involves capturing, via the microphone, audio data representing reflections of the audio content within an area in which the playback device is located.

At block 312, the method 300 involves determining, via the playback device, an acoustic response of the area in which the playback device is located based on at least the captured audio data.

At block 314, the method 300 involves selecting, via the playback device, a stored acoustic response from the acoustic response database that is most similar to the determined acoustic response of the area in which the playback device is located.

At block 316, the method 300 involves applying to the audio content, via the playback device, a set of stored audio calibration settings associated with the selected stored acoustic area response.

In some embodiments, the method 300 further involves receiving, from the accelerometer, data indicating motion of the playback device. In response to receiving data indicating motion of the playback device, the playback device suspends the equalization calibration of the playback device.

FIG. 4 shows an example embodiment of a method 400 for calibrating a playback device. The method 400 can be implemented by any of the playback devices disclosed and/or described herein, or any other playback device now known or later developed, as well as by other devices or systems of devices disclosed herein or by any suitable device.

Various embodiments of the method 400 include one or more operations, functions, and actions illustrated by blocks 402 through 414. Although the blocks are illustrated in sequential order, these blocks may also be performed in parallel, and/or in a different order than the order disclosed and described herein. Also, the various blocks may be combined into fewer blocks, divided into additional blocks, and/or removed based upon a desired implementation.

In addition, for the method 400 and for other processes and methods disclosed herein, the flowcharts show functionality and operation of one possible implementation of some embodiments. In this regard, each block may represent a module, a segment, or a portion of program code, which includes one or more instructions executable by one or more processors for implementing specific logical functions or steps in the process. The program code may be stored on any type of computer readable medium, for example, such as a storage device including a disk or hard drive. The computer readable medium may include non-transitory computer readable media, for example, such as tangible, non-transitory computer-readable media that stores data for short periods of time like register memory, processor cache, and Random Access Memory (RAM). The computer readable medium may also include non-transitory media, such as secondary or persistent long term storage, like read only memory (ROM), optical or magnetic disks, compact-disc read only memory (CD-ROM), for example. The computer readable media may also be any other volatile or non-volatile storage systems. The computer readable medium may be considered a computer readable storage medium, for example, or a tangible storage device. In addition, for the methods 400 and for other processes and methods disclosed herein, each block in FIG. 4 may represent circuitry that is wired to perform the specific logical functions in the process.

The method 400 involves calibrating a portable playback device using a PCA-based room estimation.

At block 402, the method 400 includes determining one or more PCA-based transfer functions to facilitate estimation of a room response. In particular, example transfer functions may map a playback device self-response to an estimation of a room response. Example transfer functions may be derived from a principle component analysis of a dataset of measured room responses.

Examples of PCA-based transfer functions, datasets, and associated techniques are described in Appendix C of the specification. Within examples, the PCA-based transfer functions may be derived from a PCA of a global dataset or may be derived from multiple PCAs on localized portions of the global dataset based on one or more factors, as described in Appendix C. Further examples are possible.

The dataset may include representations of multiple room responses (e.g., in the form of room-average power spectral densities (PSD). Such room responses may be measured by multiple performing the multi-location calibration process repeatedly in various locations in a plurality of different rooms or other listening environments (e.g., outdoors). To obtain a statistically sufficient dataset of different room responses and corresponding calibration settings, this process can be performed by a large number of users in a larger number of different rooms. In some examples, an initial database may be built by designated individual (e.g., product testers) and refined over time by other users. Datasets for different playback device implementations (e.g., with different numbers and arrangements of transducers, in various housings) may be collected.

At block 404, the method 400 includes determining that the playback device is to perform a calibration. Various triggers, including user-based and playback device-based triggers may initiate calibration.

At block 406, the method 400 includes outputting audio content. For instance, the playback device may output audio content via one or more speakers. The audio content may be a calibration audio signal or other content that has output over portions of the frequency range that is to be calibrated (e.g., music). Other examples are possible as well.

At block 408, the method 400 includes measuring the self-response of the playback device via one or more microphones. The self-response may refer to the echo path, which may take the form of the acoustic impulse response between the one or more speakers and the one or more microphones. Further details are described in Appendix C.

In some examples, the playback device may include an acoustic echo canceller (AEC) (e.g., to facilitate voice processing) in the presence of audio playback. Some implementations may involve measurement of the echo path from the output of the acoustic echo canceller, which may reduce the presence of echoes, reverberation, and the like from the acoustic impulse response. In some instances, this may improve the quality of the measurement (e.g., by lowering the signal-to-noise ratio) of the self-response.

At block 410, the method 400 includes estimating a room response based on the measured self-response and a PCA-based transfer function. For instance, the playback device may map the self-response to an estimated room response using a particular PCA-based transfer function. Additional details are described in Appendix C. Further examples are possible as well.

At block 412, the method 400 includes determining calibration settings based on the estimated room response. For instance, the playback device may determine calibration settings that, when applied to output of the playback device, at least partially offset acoustic characteristics of the environment which are represented in the estimated room response. In various examples, the calibration settings may take the form of an equalization (e.g., one or more filters). Further examples and details are described in Appendix C.

At block 414, the method 400 includes applying the determined calibration settings to playback by the playback device. For instance, the playback device may apply the equalization or filter, which modifies output of the playback device. Further examples are possible as well.

VI. Additional Examples

FIG. 5A is a first isometric view of an example portable playback device 410. As shown in FIG. 5A, the portable playback device 510 includes a housing 564 comprising an upper portion 568, a lower portion 566 and an intermediate portion 562 (e.g., a grille). The grille of the intermediate portion 562 allows sound to pass through from the one or more transducers positioned within the housing 564.

A plurality of ports, holes or apertures 558 in the upper portion 568 allow sound to pass through to one or more microphones positioned within the housing 564. These microphones may be utilized in the example calibration techniques disclosed herein.

The upper portion 568 further includes a user interface 560. The user interface 560 includes a plurality of control surfaces (e.g., buttons, knobs, capacitive surfaces) including playback and activation controls (e.g., a previous control, a next control, a play and/or pause control). The user interface 560 is configured to receive touch input corresponding to activation and deactivation of the one or microphones.

FIG. 5B is a second isometric view of the portable playback device 510. As shown in FIG. 5B, the intermediate portion 562 further includes a user interface 572. The user interface 572 includes a plurality of control surfaces (e.g., buttons, knobs, capacitive surfaces) including playback, activation controls (e.g., a power toggle button, a Bluetooth device discovery control, etc.), and a carrying handle 575. The lower portion 566 also includes a power receptacle 574, as shown.

FIG. 6 is a top view of a playback device base 676 to be used in conjunction with a portable playback device, such as playback device 510. As shown in FIG. 6 , the playback device base 676 includes a device receptacle 678, a power cord 680, and a power plug 682.

The device receptacle 678 is configured to receive playback device 510. The device receptacle 678 further includes a connection port 684 compatible with the playback device 510. As shown in FIG. 6 , in some embodiments, the receptacle 678 may be a loop. Many other examples are possible.

In some embodiments, the power cord 680 is compatible with an electrical outlet. In other embodiments, the power cord 680 may be compatible with a USB port. In another embodiment, the power cord 680 may be compatible with both an electrical outlet and a USB port by way of detachable pieces, for example.

As described above, when on the playback device base 676, the portable playback device 510 may initiate calibration. When removed from the playback device base 676, the portable playback device 510 may suspend calibration until the portable device 510 is stationary again. Further, when on the playback device base 676, the portable playback device base 676 may provide power (i.e., battery recharging) to portable playback device 510.

VII. Conclusion

The above discussions relating to playback devices, controller devices, playback zone configurations, and media content sources provide only some examples of operating environments within which functions and methods described below may be implemented. Other operating environments and configurations of media playback systems, playback devices, and network devices not explicitly described herein may also be applicable and suitable for implementation of the functions and methods.

The description above discloses, among other things, various example systems, methods, apparatus, and articles of manufacture including, among other components, firmware and/or software executed on hardware. It is understood that such examples are merely illustrative and should not be considered as limiting. For example, it is contemplated that any or all of the firmware, hardware, and/or software aspects or components can be embodied exclusively in hardware, exclusively in software, exclusively in firmware, or in any combination of hardware, software, and/or firmware. Accordingly, the examples provided are not the only ways) to implement such systems, methods, apparatus, and/or articles of manufacture.

Additionally, references herein to “embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one example embodiment of an invention. The appearances of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. As such, the embodiments described herein, explicitly and implicitly understood by one skilled in the art, can be combined with other embodiments.

The present technology is illustrated, for example, according to various aspects described below. Various examples of aspects of the present technology are described as numbered examples (1, 2, 3, etc.) for convenience. These are provided as examples and do not limit the present technology. It is noted that any of the dependent examples may be combined in any combination, and placed into a respective independent example. The other examples can be presented in a similar manner.

Example 1: A method comprising: determining one or more transfer functions to estimate room response based on a principle component analysis (PCA) of a dataset; determining that the playback device is to perform a calibration; outputting audio content; measuring a self-response via one or more microphones; estimating a room response based on the measured self-response and PCA-based transfer function; determining calibration settings based on the estimated room response; and applying the determined calibration settings to playback by the playback device.

Example 2: The method of example 1, wherein determining one or more transfer functions comprises determining a first transfer function based on a first PCA of a first localized portion of the dataset and determining a second transfer function based on a second PCA of a second localized portion of the dataset.

Example 3: The method of any of examples 1-2, wherein determining one or more transfer functions comprises determining one or more transfer functions based on a PCA of a global dataset.

Example 4: The method of any of examples 1-3, wherein measuring the self-response via the one or more microphones comprises measuring the self-response from the output of an acoustic echo canceller configured to cancel echo from the playback device as captured by the one or more microphones.

Example 5: A playback device configured to perform the method of any of examples 1-4.

Example 6: A tangible, non-transitory computer-readable medium having stored therein instructions executable by one or more processors to cause a device to perform the method of any of features 1-4.

Example 7: A system configured to perform the method of any of features 1-4.

The specification is presented largely in terms of illustrative environments, systems, procedures, steps, logic blocks, processing, and other symbolic representations that directly or indirectly resemble the operations of data processing devices coupled to networks. These process descriptions and representations are typically used by those skilled in the art to most effectively convey the substance of their work to others skilled in the art. Numerous specific details are set forth to provide a thorough understanding of the present disclosure. However, it is understood to those skilled in the art that certain embodiments of the present disclosure can be practiced without certain, specific details. In other instances, well known methods, procedures, components, and circuitry have not been described in detail to avoid unnecessarily obscuring aspects of the embodiments. Accordingly, the scope of the present disclosure is defined by the appended claims rather than the foregoing description of embodiments.

When any of the appended claims are read to cover a purely software and/or firmware implementation, at least one of the elements in at least one example is hereby expressly defined to include a tangible, non-transitory medium such as a memory, DVD, CD, Blu-ray, and so on, storing the software and/or firmware. 

1. A system comprising: a playback device comprising one or more microphones and at least one loudspeaker; at least one processor; and at least one non-transitory computer-readable medium comprising program instructions that are executable by the at least one processor such that the system is configured to: play back first audio content via the at least one loudspeaker; during output of the first audio content, capture, via the one or more microphones, microphone data representing playback of the first audio content in an acoustic environment; determine a self-response of the playback device in the acoustic environment based on the captured microphone data; estimate a room response of the acoustic environment, wherein the program instructions that are executable by the at least one processor such that the system is configured to estimate the room response comprise program instructions that are executable by the at least one processor such that the system is configured to: input the determined self-response to one or more transfer functions that are derived from a principle component analysis (PCA) of a dataset comprising a plurality of measured room responses such that the one or more transfer functions map determined self-responses to estimated room responses; determine calibration settings that at least partially offset acoustic characteristics represented in the estimated room response; and apply the determined calibration settings during playback of second audio content via the at least loudspeaker.
 2. The system of claim 1, wherein the at least one non-transitory computer-readable medium further comprises program instructions that are executable by the at least one processor such that the system is configured to: determine the one or more transfer functions from the principle component analysis (PCA) of the dataset comprising the plurality of measured room responses.
 3. The system of claim 2, wherein the program instructions that are executable by the at least one processor such that the system is configured to determine the one or more transfer functions comprise program instructions that are executable by the at least one processor such that the system is configured to: determine a first transfer function based on a first PCA of a first localized portion of the dataset; and determine a second transfer function based on a second PCA of a second localized portion of the dataset.
 4. The system of claim 2, wherein the dataset comprising the plurality of measured room responses is a global dataset of measured room responses of different types of acoustic environments, wherein the program instructions that are executable by the at least one processor such that the system is configured to determine the one or more transfer functions comprise program instructions that are executable by the at least one processor such that the system is configured to: determine the one or more transfer functions based on a PCA of the global dataset.
 5. The system of claim 1, further comprising one or more computing devices that are remote from the playback device, wherein the program instructions that are executable by the at least one processor such that the system is configured to determine the one or more transfer functions comprise program instructions that are executable by the at least one processor such that the system is configured to: determine the one or more transfer functions via the one or more one or more computing devices, wherein the at least one non-transitory computer-readable medium further comprises program instructions that are executable by the at least one processor such that the system is configured to: send, via a network interface, data representing the determined one or more transfer functions to the playback device.
 6. The system of claim 4, wherein the playback device comprises data storage of a first size, and wherein the global dataset is a second size that is larger than the first size.
 7. The system of claim 1, wherein the program instructions that are executable by the at least one processor such that the system is configured to determine the calibration settings comprise program instructions that are executable by the at least one processor such that the system is configured to: query a database of calibration settings for particular calibration settings that were predetermined for a particular room response that most closely matches the estimated room response.
 8. The system of claim 7, wherein the playback device comprises a network interface, and wherein the program instructions that are executable by the at least one processor such that the system is configured to query the database of calibration settings comprise program instructions that are executable by the at least one processor such that the system is configured to: send, via the network interface to a computing system, a query of the database of calibration settings.
 9. The system of claim 7, wherein the particular room response is a multi-location response representing a combination of multiple measured room responses of similar acoustic environments.
 10. The system of claim 1, wherein the program instructions that are executable by the at least one processor such that the system is configured to determine the self-response of the playback device comprise program instructions that are executable by the at least one processor such that the system is configured to: measure the self-response from the output of an acoustic echo canceller configured to cancel echo from the playback device as captured by the one or more microphones.
 11. A playback device comprising: a network interface; one or more microphones; at least one loudspeaker; a loudspeaker housing carrying the network interface, the one or more microphones, and the at least one loudspeaker; at least one processor; and at least one non-transitory computer-readable medium comprising program instructions that are executable by the at least one processor such that the playback device is configured to: play back first audio content via the at least one loudspeaker; during output of the first audio content, capture, via the one or more microphones, microphone data representing playback of the first audio content in an acoustic environment; determine a self-response of the playback device in the acoustic environment based on the captured microphone data; estimate a room response of the acoustic environment, wherein the program instructions that are executable by the at least one processor such that the playback device is configured to estimate the room response comprise program instructions that are executable by the at least one processor such that the playback device is configured to: input the determined self-response to one or more transfer functions that are derived from a principle component analysis (PCA) of a dataset comprising a plurality of measured room responses such that the one or more transfer functions map determined self-responses to estimated room responses; determine calibration settings that at least partially offset acoustic characteristics represented in the estimated room response; and apply the determined calibration settings during playback of second audio content via the at least loudspeaker.
 12. The playback device of claim 11, wherein the at least one non-transitory computer-readable medium further comprises program instructions that are executable by the at least one processor such that the playback device is configured to: receive, via the network interface from a computing system, data representing the one or more transfer functions.
 13. The playback device of claim 11, wherein the at least one non-transitory computer-readable medium further comprises program instructions that are executable by the at least one processor such that the playback device is configured to: receive, via the network interface from a smartphone, data representing instructions to play back the second audio content.
 14. The playback device of claim 11, wherein the program instructions that are executable by the at least one processor such that the playback device is configured to determine the calibration settings comprise program instructions that are executable by the at least one processor such that the playback device is configured to: query a database of calibration settings for particular calibration settings that were predetermined for a particular room response that most closely matches the estimated room response.
 15. The playback device of claim 14, wherein the playback device comprises a network interface, and wherein the program instructions that are executable by the at least one processor such that the system is configured to query the database of calibration settings comprise program instructions that are executable by the at least one processor such that the system is configured to: send, via the network interface to a computing system, a query of the database of calibration settings.
 16. The playback device of claim 11, wherein the playback device further comprises at least one battery carried by the housing, and wherein the at least one non-transitory computer-readable medium further comprises program instructions that are executable by the at least one processor such that the playback device is configured to: detect that a battery level of the at least one battery has decreased to a threshold level; and based on detection that the battery level of the at least one battery has decreased to the threshold level, disable periodic self-calibration of the playback device, wherein self-calibration of the playback device comprises capture of the microphone data representing playback of the first audio content in an acoustic environment, determination of the self-response of the playback device, estimation of the room response, and determination of the self-response of the playback device in the acoustic environment based on the captured microphone data.
 17. The playback device of claim 11, wherein the program instructions that are executable by the at least one processor such that the playback device is configured to determine the self-response of the playback device comprise program instructions that are executable by the at least one processor such that the playback device is configured to: measure the self-response from the output of an acoustic echo canceller configured to cancel echo from the playback device as captured by the one or more microphones.
 18. At least one non-transitory computer-readable medium comprising program instructions that are executable by at least one processor such that a playback device is configured to: play back first audio content via at least one loudspeaker; during output of the first audio content, capture, via one or more microphones, microphone data representing playback of the first audio content in an acoustic environment; determine a self-response of the playback device in the acoustic environment based on the captured microphone data; estimate a room response of the acoustic environment, wherein the program instructions that are executable by the at least one processor such that the playback device is configured to estimate the room response comprise program instructions that are executable by the at least one processor such that the playback device is configured to: input the determined self-response to one or more transfer functions that are derived from a principle component analysis (PCA) of a dataset comprising a plurality of measured room responses such that the one or more transfer functions map determined self-responses to estimated room responses; determine calibration settings that at least partially offset acoustic characteristics represented in the estimated room response; and apply the determined calibration settings during playback of second audio content via the at least loudspeaker.
 19. The at least one non-transitory computer-readable medium of claim 18, wherein the program instructions that are executable by the at least one processor such that the playback device is configured to determine the calibration settings comprise program instructions that are executable by the at least one processor such that the playback device is configured to: query a database of calibration settings for particular calibration settings that were predetermined for a particular room response that most closely matches the estimated room response.
 20. The at least one non-transitory computer-readable medium of claim 18, wherein the program instructions that are executable by the at least one processor such that the playback device is configured to determine the self-response of the playback device comprise program instructions that are executable by the at least one processor such that the playback device is configured to: measure the self-response from the output of an acoustic echo canceller configured to cancel echo from the playback device as captured by the one or more microphones. 